# Glossary

- Reference [Glossary of Web Terms](https://developer.mozilla.org/en-US/docs/Glossary)

## Web Terms

This glossary contains comprehensive web terms categorized across 15 domains:

- HTML & Markup
- CSS & Styling  
- JavaScript & Programming
- Web APIs & DOM
- HTTP & Networking
- Security & Authentication
- Performance & Optimization
- Accessibility
- Web Protocols & Standards
- Browsers & Engines
- Development Tools
- Data Formats & Encoding
- Media & Graphics
- Architecture & Patterns
- Servers & Infrastructure

## All Web Terms

- [Abstraction](https://developer.mozilla.org/en-US/docs/Glossary/Abstraction)
- [Accent](https://developer.mozilla.org/en-US/docs/Glossary/Accent)
- [Accessibility](https://developer.mozilla.org/en-US/docs/Glossary/Accessibility)
- [Accessibility tree](https://developer.mozilla.org/en-US/docs/Glossary/Accessibility_tree)
- [Accessible description](https://developer.mozilla.org/en-US/docs/Glossary/Accessible_description)
- [Accessible name](https://developer.mozilla.org/en-US/docs/Glossary/Accessible_name)
- [Adobe Flash](https://developer.mozilla.org/en-US/docs/Glossary/Adobe_Flash)
- [Advance measure](https://developer.mozilla.org/en-US/docs/Glossary/Advance_measure)
- [Ajax](https://developer.mozilla.org/en-US/docs/Glossary/Ajax)
- [Algorithm](https://developer.mozilla.org/en-US/docs/Glossary/Algorithm)
- [Alignment container](https://developer.mozilla.org/en-US/docs/Glossary/Alignment_container)
- [Alignment subject](https://developer.mozilla.org/en-US/docs/Glossary/Alignment_subject)
- [Alpha (*alpha channel*)](https://developer.mozilla.org/en-US/docs/Glossary/Alpha)
- [ALPN](https://developer.mozilla.org/en-US/docs/Glossary/ALPN)
- [API](https://developer.mozilla.org/en-US/docs/Glossary/API)
- [Apple Safari](https://developer.mozilla.org/en-US/docs/Glossary/Apple_Safari)
- [Application context](https://developer.mozilla.org/en-US/docs/Glossary/Application_context)
- [Argument](https://developer.mozilla.org/en-US/docs/Glossary/Argument)
- [ARIA](https://developer.mozilla.org/en-US/docs/Glossary/ARIA)
- [ARPA](https://developer.mozilla.org/en-US/docs/Glossary/ARPA)
- [ARPANET](https://developer.mozilla.org/en-US/docs/Glossary/ARPANET)
- [Array](https://developer.mozilla.org/en-US/docs/Glossary/Array)
- [ASCII](https://developer.mozilla.org/en-US/docs/Glossary/ASCII)
- [Aspect ratio](https://developer.mozilla.org/en-US/docs/Glossary/Aspect_ratio)
- [Asynchronous](https://developer.mozilla.org/en-US/docs/Glossary/Asynchronous)
- [ATAG](https://developer.mozilla.org/en-US/docs/Glossary/ATAG)
- [Attribute](https://developer.mozilla.org/en-US/docs/Glossary/Attribute)
- [Authentication](https://developer.mozilla.org/en-US/docs/Glossary/Authentication)
- [Authenticator](https://developer.mozilla.org/en-US/docs/Glossary/Authenticator)
- [Bandwidth](https://developer.mozilla.org/en-US/docs/Glossary/Bandwidth)
- [Base64](https://developer.mozilla.org/en-US/docs/Glossary/Base64)
- [Baseline](https://developer.mozilla.org/en-US/docs/Glossary/Baseline)
  - [Baseline (*compatibility*)](https://developer.mozilla.org/en-US/docs/Glossary/Baseline/Compatibility)
  - [Baseline (*typography*)](https://developer.mozilla.org/en-US/docs/Glossary/Baseline/Typography)
- [BCP 47 language tag](https://developer.mozilla.org/en-US/docs/Glossary/BCP_47_language_tag)
- [Beacon](https://developer.mozilla.org/en-US/docs/Glossary/Beacon)
- [Bézier curve](https://developer.mozilla.org/en-US/docs/Glossary/Bézier_curve)
- [bfcache](https://developer.mozilla.org/en-US/docs/Glossary/bfcache)
- [BiDi](https://developer.mozilla.org/en-US/docs/Glossary/BiDi)
- [BigInt](https://developer.mozilla.org/en-US/docs/Glossary/BigInt)
- [Binding](https://developer.mozilla.org/en-US/docs/Glossary/Binding)
- [Bitwise flags](https://developer.mozilla.org/en-US/docs/Glossary/Bitwise_flags)
- [Blink](https://developer.mozilla.org/en-US/docs/Glossary/Blink)
  - [blink element (*\<blink\> tag*)](https://developer.mozilla.org/en-US/docs/Glossary/blink_element)
- [Block](https://developer.mozilla.org/en-US/docs/Glossary/Block)
  - [Block (*CSS*)](https://developer.mozilla.org/en-US/docs/Glossary/Block/CSS)
  - [Block (*scripting*)](https://developer.mozilla.org/en-US/docs/Glossary/Block/Scripting)
- [Block cipher mode of operation](https://developer.mozilla.org/en-US/docs/Glossary/Block_cipher_mode_of_operation)
- [Block-level content](https://developer.mozilla.org/en-US/docs/Glossary/Block-level_content)
- [Boolean](https://developer.mozilla.org/en-US/docs/Glossary/Boolean)
  - [Boolean (*JavaScript*)](https://developer.mozilla.org/en-US/docs/Glossary/Boolean/JavaScript)
  - [Boolean attribute (*ARIA*)](https://developer.mozilla.org/en-US/docs/Glossary/Boolean/ARIA)
  - [Boolean attribute (*HTML*)](https://developer.mozilla.org/en-US/docs/Glossary/Boolean/HTML)
- [Bounding box](https://developer.mozilla.org/en-US/docs/Glossary/Bounding_box)
- [Breadcrumb](https://developer.mozilla.org/en-US/docs/Glossary/Breadcrumb)
- [Brotli compression](https://developer.mozilla.org/en-US/docs/Glossary/Brotli_compression)
- [Browser](https://developer.mozilla.org/en-US/docs/Glossary/Browser)
- [Browsing context](https://developer.mozilla.org/en-US/docs/Glossary/Browsing_context)
- [Buffer](https://developer.mozilla.org/en-US/docs/Glossary/Buffer)
- [Bun](https://developer.mozilla.org/en-US/docs/Glossary/Bun)
- [Cache](https://developer.mozilla.org/en-US/docs/Glossary/Cache)
- [Cacheable](https://developer.mozilla.org/en-US/docs/Glossary/Cacheable)
- [CalDAV](https://developer.mozilla.org/en-US/docs/Glossary/CalDAV)
- [Call stack](https://developer.mozilla.org/en-US/docs/Glossary/Call_stack)
- [Callback function](https://developer.mozilla.org/en-US/docs/Glossary/Callback_function)
- [Camel case](https://developer.mozilla.org/en-US/docs/Glossary/Camel_case)
- [Canonical order](https://developer.mozilla.org/en-US/docs/Glossary/Canonical_order)
- [Canvas](https://developer.mozilla.org/en-US/docs/Glossary/Canvas)
- [Card sorting](https://developer.mozilla.org/en-US/docs/Glossary/Card_sorting)
- [CardDAV](https://developer.mozilla.org/en-US/docs/Glossary/CardDAV)
- [Caret](https://developer.mozilla.org/en-US/docs/Glossary/Caret)
- [CDN](https://developer.mozilla.org/en-US/docs/Glossary/CDN)
- [Certificate authority](https://developer.mozilla.org/en-US/docs/Glossary/Certificate_authority)
- [Certified](https://developer.mozilla.org/en-US/docs/Glossary/Certified)
- [Challenge-response authentication](https://developer.mozilla.org/en-US/docs/Glossary/Challenge-response_authentication)
- [Character](https://developer.mozilla.org/en-US/docs/Glossary/Character)
- [Character encoding](https://developer.mozilla.org/en-US/docs/Glossary/Character_encoding)
- [Character reference](https://developer.mozilla.org/en-US/docs/Glossary/Character_reference)
- [Character set](https://developer.mozilla.org/en-US/docs/Glossary/Character_set)
- [Chrome](https://developer.mozilla.org/en-US/docs/Glossary/Chrome)
- [CIA](https://developer.mozilla.org/en-US/docs/Glossary/CIA)
- [Cipher](https://developer.mozilla.org/en-US/docs/Glossary/Cipher)
- [Cipher suite](https://developer.mozilla.org/en-US/docs/Glossary/Cipher_suite)
- [Ciphertext](https://developer.mozilla.org/en-US/docs/Glossary/Ciphertext)
- [Class](https://developer.mozilla.org/en-US/docs/Glossary/Class)
- [Client-side rendering (*CSR*)](https://developer.mozilla.org/en-US/docs/Glossary/Client-side_rendering_(CSR))
- [Closure](https://developer.mozilla.org/en-US/docs/Glossary/Closure)
- [Cloud](https://developer.mozilla.org/en-US/docs/Glossary/Cloud)
- [Cloud computing](https://developer.mozilla.org/en-US/docs/Glossary/Cloud_computing)
- [CMS](https://developer.mozilla.org/en-US/docs/Glossary/CMS)
- [Code point](https://developer.mozilla.org/en-US/docs/Glossary/Code_point)
- [Code splitting](https://developer.mozilla.org/en-US/docs/Glossary/Code_splitting)
- [Code unit](https://developer.mozilla.org/en-US/docs/Glossary/Code_unit)
- [Codec](https://developer.mozilla.org/en-US/docs/Glossary/Codec)
- [Color space](https://developer.mozilla.org/en-US/docs/Glossary/Color_space)
- [Color wheel](https://developer.mozilla.org/en-US/docs/Glossary/Color_wheel)
- [Compile](https://developer.mozilla.org/en-US/docs/Glossary/Compile)
- [Compile time](https://developer.mozilla.org/en-US/docs/Glossary/Compile_time)
- [Composite operation](https://developer.mozilla.org/en-US/docs/Glossary/Composite_operation)
- [Compression Dictionary Transport](https://developer.mozilla.org/en-US/docs/Glossary/Compression_Dictionary_Transport)
- [Computer programming](https://developer.mozilla.org/en-US/docs/Glossary/Computer_programming)
- [Conditional](https://developer.mozilla.org/en-US/docs/Glossary/Conditional)
- [Constant](https://developer.mozilla.org/en-US/docs/Glossary/Constant)
- [Constructor](https://developer.mozilla.org/en-US/docs/Glossary/Constructor)
- [Content header](https://developer.mozilla.org/en-US/docs/Glossary/Content_header)
- [Continuous integration](https://developer.mozilla.org/en-US/docs/Glossary/Continuous_integration)
- [Continuous media](https://developer.mozilla.org/en-US/docs/Glossary/Continuous_media)
- [Control flow](https://developer.mozilla.org/en-US/docs/Glossary/Control_flow)
- [Cookie](https://developer.mozilla.org/en-US/docs/Glossary/Cookie)
- [Copyleft](https://developer.mozilla.org/en-US/docs/Glossary/Copyleft)
- [CORS](https://developer.mozilla.org/en-US/docs/Glossary/CORS)
- [CORS-safelisted request header](https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted_request_header)
- [CORS-safelisted response header](https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted_response_header)
- [Crawler](https://developer.mozilla.org/en-US/docs/Glossary/Crawler)
- [Credential](https://developer.mozilla.org/en-US/docs/Glossary/Credential)
- [CRLF](https://developer.mozilla.org/en-US/docs/Glossary/CRLF)
- [Cross Axis](https://developer.mozilla.org/en-US/docs/Glossary/Cross_Axis)
- [Cross-site request forgery (*CSRF*)](https://developer.mozilla.org/en-US/docs/Glossary/CSRF)
- [Cross-site scripting (*XSS*)](https://developer.mozilla.org/en-US/docs/Glossary/Cross-site_scripting)
- [CRUD](https://developer.mozilla.org/en-US/docs/Glossary/CRUD)
- [Cryptanalysis](https://developer.mozilla.org/en-US/docs/Glossary/Cryptanalysis)
- [Cryptography](https://developer.mozilla.org/en-US/docs/Glossary/Cryptography)
- [CSP](https://developer.mozilla.org/en-US/docs/Glossary/CSP)
- [CSS](https://developer.mozilla.org/en-US/docs/Glossary/CSS)
- [CSS Object Model (*CSSOM*)](https://developer.mozilla.org/en-US/docs/Glossary/CSS_Object_Model_(CSSOM))
- [CSS pixel](https://developer.mozilla.org/en-US/docs/Glossary/CSS_pixel)
- [CSS preprocessor](https://developer.mozilla.org/en-US/docs/Glossary/CSS_preprocessor)
- [Cumulative Layout Shift (*CLS*)](https://developer.mozilla.org/en-US/docs/Glossary/CLS)
- [Data structure](https://developer.mozilla.org/en-US/docs/Glossary/Data_structure)
- [Database](https://developer.mozilla.org/en-US/docs/Glossary/Database)
- [Debounce](https://developer.mozilla.org/en-US/docs/Glossary/Debounce)
- [Decryption](https://developer.mozilla.org/en-US/docs/Glossary/Decryption)
- [Deep copy](https://developer.mozilla.org/en-US/docs/Glossary/Deep_copy)
- [Delta](https://developer.mozilla.org/en-US/docs/Glossary/Delta)
- [Denial of Service (*DoS*)](https://developer.mozilla.org/en-US/docs/Glossary/Denial_of_Service)
- [Deno](https://developer.mozilla.org/en-US/docs/Glossary/Deno)
- [Descriptor (*CSS*)](https://developer.mozilla.org/en-US/docs/Glossary/Descriptor_(CSS))
- [Deserialization](https://developer.mozilla.org/en-US/docs/Glossary/Deserialization)
- [Developer tools](https://developer.mozilla.org/en-US/docs/Glossary/Developer_tools)
- [Device pixel](https://developer.mozilla.org/en-US/docs/Glossary/Device_pixel)
- [Digital certificate](https://developer.mozilla.org/en-US/docs/Glossary/Digital_certificate)
- [Digital signature](https://developer.mozilla.org/en-US/docs/Glossary/Digital_signature)
- [Distributed Denial of Service (*DDoS*)](https://developer.mozilla.org/en-US/docs/Glossary/Distributed_Denial_of_Service)
- [DMZ](https://developer.mozilla.org/en-US/docs/Glossary/DMZ)
- [DNS](https://developer.mozilla.org/en-US/docs/Glossary/DNS)
- [Doctype](https://developer.mozilla.org/en-US/docs/Glossary/Doctype)
- [Document directive](https://developer.mozilla.org/en-US/docs/Glossary/Document_directive)
- [Document environment](https://developer.mozilla.org/en-US/docs/Glossary/Document_environment)
- [DOM (*Document Object Model*)](https://developer.mozilla.org/en-US/docs/Glossary/DOM)
- [Domain](https://developer.mozilla.org/en-US/docs/Glossary/Domain)
- [Domain name](https://developer.mozilla.org/en-US/docs/Glossary/Domain_name)
- [Domain sharding](https://developer.mozilla.org/en-US/docs/Glossary/Domain_sharding)
- [Dominator](https://developer.mozilla.org/en-US/docs/Glossary/Dominator)
- [DSL](https://developer.mozilla.org/en-US/docs/Glossary/DSL)
  - [DSL (*Digital Subscriber Line*)](https://developer.mozilla.org/en-US/docs/Glossary/DSL/Digital_Subscriber_Line)
  - [DSL (*Domain-Specific Language*)](https://developer.mozilla.org/en-US/docs/Glossary/DSL/Domain-Specific_Language)
- [DTLS (*Datagram Transport Layer Security*)](https://developer.mozilla.org/en-US/docs/Glossary/DTLS)
- [DTMF (*Dual-Tone Multi-Frequency signaling*)](https://developer.mozilla.org/en-US/docs/Glossary/DTMF)
- [Dynamic typing](https://developer.mozilla.org/en-US/docs/Glossary/Dynamic_typing)
- [ECMA](https://developer.mozilla.org/en-US/docs/Glossary/ECMA)
- [ECMAScript](https://developer.mozilla.org/en-US/docs/Glossary/ECMAScript)
- [Effective connection type](https://developer.mozilla.org/en-US/docs/Glossary/Effective_connection_type)
- [Element](https://developer.mozilla.org/en-US/docs/Glossary/Element)
- [Encapsulation](https://developer.mozilla.org/en-US/docs/Glossary/Encapsulation)
- [Encryption](https://developer.mozilla.org/en-US/docs/Glossary/Encryption)
- [Endianness](https://developer.mozilla.org/en-US/docs/Glossary/Endianness)
- [Engine](https://developer.mozilla.org/en-US/docs/Glossary/Engine)
- [JavaScript engine](https://developer.mozilla.org/en-US/docs/Glossary/JavaScript_engine)
- [Rendering engine](https://developer.mozilla.org/en-US/docs/Glossary/Rendering_engine)
- [Entity](https://developer.mozilla.org/en-US/docs/Glossary/Entity)
- [Entity header](https://developer.mozilla.org/en-US/docs/Glossary/Entity_header)
- [Enumerated](https://developer.mozilla.org/en-US/docs/Glossary/Enumerated)
- [Escape character](https://developer.mozilla.org/en-US/docs/Glossary/Escape_character)
- [Event](https://developer.mozilla.org/en-US/docs/Glossary/Event)
- [Exception](https://developer.mozilla.org/en-US/docs/Glossary/Exception)
- [EXIF](https://developer.mozilla.org/en-US/docs/Glossary/EXIF)
- [Expando](https://developer.mozilla.org/en-US/docs/Glossary/Expando)
- [Extrinsic size](https://developer.mozilla.org/en-US/docs/Glossary/Extrinsic_size)
- [Fallback alignment](https://developer.mozilla.org/en-US/docs/Glossary/Fallback_alignment)
- [Falsy](https://developer.mozilla.org/en-US/docs/Glossary/Falsy)
- [Favicon](https://developer.mozilla.org/en-US/docs/Glossary/Favicon)
- [Federated identity](https://developer.mozilla.org/en-US/docs/Glossary/Federated_identity)
- [Fetch directive](https://developer.mozilla.org/en-US/docs/Glossary/Fetch_directive)
- [Fetch metadata request header](https://developer.mozilla.org/en-US/docs/Glossary/Fetch_metadata_request_header)
- [Fingerprinting](https://developer.mozilla.org/en-US/docs/Glossary/Fingerprinting)
- [Firefox OS](https://developer.mozilla.org/en-US/docs/Glossary/Firefox_OS)
- [Firewall](https://developer.mozilla.org/en-US/docs/Glossary/Firewall)
- [First Contentful Paint (*FCP*)](https://developer.mozilla.org/en-US/docs/Glossary/First_Contentful_Paint_(FCP))
- [First CPU idle](https://developer.mozilla.org/en-US/docs/Glossary/First_CPU_idle)
- [First Input Delay (FID)Deprecated](https://developer.mozilla.org/en-US/docs/Glossary/First_Input_Delay)
- [First Meaningful Paint (*FMP*)](https://developer.mozilla.org/en-US/docs/Glossary/First_meaningful_paint)
- [First Paint (*FP*)](https://developer.mozilla.org/en-US/docs/Glossary/First_paint)
- [First-class function](https://developer.mozilla.org/en-US/docs/Glossary/First-class_function)
- [Flex](https://developer.mozilla.org/en-US/docs/Glossary/Flex)
- [Flex container](https://developer.mozilla.org/en-US/docs/Glossary/Flex_container)
- [Flex item](https://developer.mozilla.org/en-US/docs/Glossary/Flex_item)
- [Flexbox](https://developer.mozilla.org/en-US/docs/Glossary/Flexbox)
- [Flow relative values](https://developer.mozilla.org/en-US/docs/Glossary/Flow_relative_values)
- [Forbidden request header](https://developer.mozilla.org/en-US/docs/Glossary/Forbidden_request_header)
- [Forbidden response header name](https://developer.mozilla.org/en-US/docs/Glossary/Forbidden_response_header_name)
- [Fork](https://developer.mozilla.org/en-US/docs/Glossary/Fork)
- [Fragmentainer](https://developer.mozilla.org/en-US/docs/Glossary/Fragmentainer)
- [Frame rate (*FPS*)](https://developer.mozilla.org/en-US/docs/Glossary/FPS)
- [FTP](https://developer.mozilla.org/en-US/docs/Glossary/FTP)
- [FTU](https://developer.mozilla.org/en-US/docs/Glossary/FTU)
- [Function](https://developer.mozilla.org/en-US/docs/Glossary/Function)
- [Fuzz testing](https://developer.mozilla.org/en-US/docs/Glossary/Fuzz_testing)
- [Gamut](https://developer.mozilla.org/en-US/docs/Glossary/Gamut)
- [Garbage collection](https://developer.mozilla.org/en-US/docs/Glossary/Garbage_collection)
- [Gecko](https://developer.mozilla.org/en-US/docs/Glossary/Gecko)
- [General header](https://developer.mozilla.org/en-US/docs/Glossary/General_header)
- [GIF](https://developer.mozilla.org/en-US/docs/Glossary/GIF)
- [Git](https://developer.mozilla.org/en-US/docs/Glossary/Git)
- [Global object](https://developer.mozilla.org/en-US/docs/Glossary/Global_object)
- [Global scope](https://developer.mozilla.org/en-US/docs/Glossary/Global_scope)
- [Global variable](https://developer.mozilla.org/en-US/docs/Glossary/Global_variable)
- [Glyph](https://developer.mozilla.org/en-US/docs/Glossary/Glyph)
- [Google Chrome](https://developer.mozilla.org/en-US/docs/Glossary/Google_Chrome)
- [GPL](https://developer.mozilla.org/en-US/docs/Glossary/GPL)
- [GPU](https://developer.mozilla.org/en-US/docs/Glossary/GPU)
- [Graceful degradation](https://developer.mozilla.org/en-US/docs/Glossary/Graceful_degradation)
- [Grid](https://developer.mozilla.org/en-US/docs/Glossary/Grid)
- [Grid areas](https://developer.mozilla.org/en-US/docs/Glossary/Grid_areas)
- [Grid Axis](https://developer.mozilla.org/en-US/docs/Glossary/Grid_Axis)
- [Grid Cell](https://developer.mozilla.org/en-US/docs/Glossary/Grid_Cell)
- [Grid Column](https://developer.mozilla.org/en-US/docs/Glossary/Grid_Column)
- [Grid container](https://developer.mozilla.org/en-US/docs/Glossary/Grid_container)
- [Grid lines](https://developer.mozilla.org/en-US/docs/Glossary/Grid_lines)
- [Grid Row](https://developer.mozilla.org/en-US/docs/Glossary/Grid_Row)
- [Grid Tracks](https://developer.mozilla.org/en-US/docs/Glossary/Grid_Tracks)
- [Guaranteed-invalid value](https://developer.mozilla.org/en-US/docs/Glossary/Guaranteed-invalid_value)
- [Gutters](https://developer.mozilla.org/en-US/docs/Glossary/Gutters)
- [gzip compression](https://developer.mozilla.org/en-US/docs/Glossary/gzip_compression)
- [Hash function](https://developer.mozilla.org/en-US/docs/Glossary/Hash_function)
- [Hash routing](https://developer.mozilla.org/en-US/docs/Glossary/Hash_routing)
- [Head](https://developer.mozilla.org/en-US/docs/Glossary/Head)
- [High-level programming language](https://developer.mozilla.org/en-US/docs/Glossary/High-level_programming_language)
- [HMAC](https://developer.mozilla.org/en-US/docs/Glossary/HMAC)
- [Hoisting](https://developer.mozilla.org/en-US/docs/Glossary/Hoisting)
- [HOL blocking](https://developer.mozilla.org/en-US/docs/Glossary/HOL_blocking)
- [Host](https://developer.mozilla.org/en-US/docs/Glossary/Host)
- [Hotlink](https://developer.mozilla.org/en-US/docs/Glossary/Hotlink)
- [Houdini](https://developer.mozilla.org/en-US/docs/Glossary/Houdini)
- [HPKP](https://developer.mozilla.org/en-US/docs/Glossary/HPKP)
- [HSTS](https://developer.mozilla.org/en-US/docs/Glossary/HSTS)
- [HTML](https://developer.mozilla.org/en-US/docs/Glossary/HTML)
- [HTML color codes](https://developer.mozilla.org/en-US/docs/Glossary/HTML_color_codes)
- [HTML5](https://developer.mozilla.org/en-US/docs/Glossary/HTML5)
- [HTTP](https://developer.mozilla.org/en-US/docs/Glossary/HTTP)
- [HTTP content](https://developer.mozilla.org/en-US/docs/Glossary/HTTP_content)
- [HTTP header](https://developer.mozilla.org/en-US/docs/Glossary/HTTP_header)
- [HTTP/2](https://developer.mozilla.org/en-US/docs/Glossary/HTTP/2)
- [HTTP/3](https://developer.mozilla.org/en-US/docs/Glossary/HTTP/3)
- [HTTPS](https://developer.mozilla.org/en-US/docs/Glossary/HTTPS)
- [HTTPS RR](https://developer.mozilla.org/en-US/docs/Glossary/HTTPS_RR)
- [Hyperlink](https://developer.mozilla.org/en-US/docs/Glossary/Hyperlink)
- [Hypertext](https://developer.mozilla.org/en-US/docs/Glossary/Hypertext)
- [IANA](https://developer.mozilla.org/en-US/docs/Glossary/IANA)
- [ICANN](https://developer.mozilla.org/en-US/docs/Glossary/ICANN)
- [ICE](https://developer.mozilla.org/en-US/docs/Glossary/ICE)
- [IDE](https://developer.mozilla.org/en-US/docs/Glossary/IDE)
- [Idempotent](https://developer.mozilla.org/en-US/docs/Glossary/Idempotent)
- [Identifier](https://developer.mozilla.org/en-US/docs/Glossary/Identifier)
- [Identity provider (*IdP*)](https://developer.mozilla.org/en-US/docs/Glossary/Identity_provider)
- [IDL](https://developer.mozilla.org/en-US/docs/Glossary/IDL)
- [IETF](https://developer.mozilla.org/en-US/docs/Glossary/IETF)
- [IIFE](https://developer.mozilla.org/en-US/docs/Glossary/IIFE)
- [IMAP](https://developer.mozilla.org/en-US/docs/Glossary/IMAP)
- [Immutable](https://developer.mozilla.org/en-US/docs/Glossary/Immutable)
- [IndexedDB](https://developer.mozilla.org/en-US/docs/Glossary/IndexedDB)
- [Information architecture](https://developer.mozilla.org/en-US/docs/Glossary/Information_architecture)
- [Inheritance](https://developer.mozilla.org/en-US/docs/Glossary/Inheritance)
- [Ink overflow](https://developer.mozilla.org/en-US/docs/Glossary/Ink_overflow)
- [Inline-level content](https://developer.mozilla.org/en-US/docs/Glossary/Inline-level_content)
- [Input method editor](https://developer.mozilla.org/en-US/docs/Glossary/Input_method_editor)
- [Inset properties](https://developer.mozilla.org/en-US/docs/Glossary/Inset_properties)
- [Instance](https://developer.mozilla.org/en-US/docs/Glossary/Instance)
- [Interaction to Next Paint (*INP*)](https://developer.mozilla.org/en-US/docs/Glossary/interaction_to_next_paint)
- [Internationalization (*i18n*)](https://developer.mozilla.org/en-US/docs/Glossary/Internationalization)
- [Internet](https://developer.mozilla.org/en-US/docs/Glossary/Internet)
- [Interpolation](https://developer.mozilla.org/en-US/docs/Glossary/Interpolation)
- [Intrinsic size](https://developer.mozilla.org/en-US/docs/Glossary/Intrinsic_size)
- [Invariant](https://developer.mozilla.org/en-US/docs/Glossary/Invariant)
- [IP Address](https://developer.mozilla.org/en-US/docs/Glossary/IP_Address)
- [IPv4](https://developer.mozilla.org/en-US/docs/Glossary/IPv4)
- [IPv6](https://developer.mozilla.org/en-US/docs/Glossary/IPv6)
- [IRC](https://developer.mozilla.org/en-US/docs/Glossary/IRC)
- [ISO](https://developer.mozilla.org/en-US/docs/Glossary/ISO)
- [ISP](https://developer.mozilla.org/en-US/docs/Glossary/ISP)
- [ITU](https://developer.mozilla.org/en-US/docs/Glossary/ITU)
- [Jank](https://developer.mozilla.org/en-US/docs/Glossary/Jank)
- [Java](https://developer.mozilla.org/en-US/docs/Glossary/Java)
- [JavaScript](https://developer.mozilla.org/en-US/docs/Glossary/JavaScript)
- [Jitter](https://developer.mozilla.org/en-US/docs/Glossary/Jitter)
- [JPEG](https://developer.mozilla.org/en-US/docs/Glossary/JPEG)
- [JSON](https://developer.mozilla.org/en-US/docs/Glossary/JSON)
- [JSON type representation](https://developer.mozilla.org/en-US/docs/Glossary/JSON_type_representation)
- [Just-In-Time Compilation (*JIT*)](https://developer.mozilla.org/en-US/docs/Glossary/Just-in-time_compilation)
- [Kebab case](https://developer.mozilla.org/en-US/docs/Glossary/Kebab_case)
- [Key](https://developer.mozilla.org/en-US/docs/Glossary/Key)
- [Keyword](https://developer.mozilla.org/en-US/docs/Glossary/Keyword)
- [Largest Contentful Paint (*LCP*)](https://developer.mozilla.org/en-US/docs/Glossary/Largest_contentful_paint)
- [Latency](https://developer.mozilla.org/en-US/docs/Glossary/Latency)
- [Layout mode](https://developer.mozilla.org/en-US/docs/Glossary/Layout_mode)
- [Layout viewport](https://developer.mozilla.org/en-US/docs/Glossary/Layout_viewport)
- [Lazy load](https://developer.mozilla.org/en-US/docs/Glossary/Lazy_load)
- [Leading](https://developer.mozilla.org/en-US/docs/Glossary/Leading)
- [LGPL](https://developer.mozilla.org/en-US/docs/Glossary/LGPL)
- [Ligature](https://developer.mozilla.org/en-US/docs/Glossary/Ligature)
- [Literal](https://developer.mozilla.org/en-US/docs/Glossary/Literal)
- [Local scope](https://developer.mozilla.org/en-US/docs/Glossary/Local_scope)
- [Local variable](https://developer.mozilla.org/en-US/docs/Glossary/Local_variable)
- [Locale](https://developer.mozilla.org/en-US/docs/Glossary/Locale)
- [Localization](https://developer.mozilla.org/en-US/docs/Glossary/Localization)
- [Logical properties](https://developer.mozilla.org/en-US/docs/Glossary/Logical_properties)
- [Long task](https://developer.mozilla.org/en-US/docs/Glossary/Long_task)
- [Loop](https://developer.mozilla.org/en-US/docs/Glossary/Loop)
- [Lossless compression](https://developer.mozilla.org/en-US/docs/Glossary/Lossless_compression)
- [Lossy compression](https://developer.mozilla.org/en-US/docs/Glossary/Lossy_compression)
- [LTR (*Left To Right*)](https://developer.mozilla.org/en-US/docs/Glossary/LTR)
- [Main axis](https://developer.mozilla.org/en-US/docs/Glossary/Main_axis)
- [Main thread](https://developer.mozilla.org/en-US/docs/Glossary/Main_thread)
- [Markup](https://developer.mozilla.org/en-US/docs/Glossary/Markup)
- [MathML](https://developer.mozilla.org/en-US/docs/Glossary/MathML)
- [Media](https://developer.mozilla.org/en-US/docs/Glossary/Media)
  - [Media (*Audio-visual presentation*)](https://developer.mozilla.org/en-US/docs/Glossary/Media/Audio-visual_presentation)
  - [Media (*CSS*)](https://developer.mozilla.org/en-US/docs/Glossary/Media/CSS)
- [Media query](https://developer.mozilla.org/en-US/docs/Glossary/Media_query)
- [Metadata](https://developer.mozilla.org/en-US/docs/Glossary/Metadata)
- [Method](https://developer.mozilla.org/en-US/docs/Glossary/Method)
- [Microsoft Edge](https://developer.mozilla.org/en-US/docs/Glossary/Microsoft_Edge)
- [Microsoft Internet Explorer](https://developer.mozilla.org/en-US/docs/Glossary/Microsoft_Internet_Explorer)
- [Middleware](https://developer.mozilla.org/en-US/docs/Glossary/Middleware)
- [MIME](https://developer.mozilla.org/en-US/docs/Glossary/MIME)
- [MIME type](https://developer.mozilla.org/en-US/docs/Glossary/MIME_type)
- [Minification](https://developer.mozilla.org/en-US/docs/Glossary/Minification)
- [MitM](https://developer.mozilla.org/en-US/docs/Glossary/MitM)
- [Mixin](https://developer.mozilla.org/en-US/docs/Glossary/Mixin)
- [Mobile first](https://developer.mozilla.org/en-US/docs/Glossary/Mobile_first)
- [Modem](https://developer.mozilla.org/en-US/docs/Glossary/Modem)
- [Modularity](https://developer.mozilla.org/en-US/docs/Glossary/Modularity)
- [Mozilla Firefox](https://developer.mozilla.org/en-US/docs/Glossary/Mozilla_Firefox)
- [Multi-factor authentication](https://developer.mozilla.org/en-US/docs/Glossary/Multi-factor_authentication)
- [Mutable](https://developer.mozilla.org/en-US/docs/Glossary/Mutable)
- [MVC](https://developer.mozilla.org/en-US/docs/Glossary/MVC)
- [Namespace](https://developer.mozilla.org/en-US/docs/Glossary/Namespace)
- [NaN](https://developer.mozilla.org/en-US/docs/Glossary/NaN)
- [NAT](https://developer.mozilla.org/en-US/docs/Glossary/NAT)
- [Native](https://developer.mozilla.org/en-US/docs/Glossary/Native)
- [Navigation directive](https://developer.mozilla.org/en-US/docs/Glossary/Navigation_directive)
- [Netscape Navigator](https://developer.mozilla.org/en-US/docs/Glossary/Netscape_Navigator)
- [Network throttling](https://developer.mozilla.org/en-US/docs/Glossary/Network_throttling)
- [NNTP](https://developer.mozilla.org/en-US/docs/Glossary/NNTP)
- [Node](https://developer.mozilla.org/en-US/docs/Glossary/Node)
  - [Node (*DOM*)](https://developer.mozilla.org/en-US/docs/Glossary/Node/DOM)
  - [Node (*networking*)](https://developer.mozilla.org/en-US/docs/Glossary/Node/Networking)
- [Node.js](https://developer.mozilla.org/en-US/docs/Glossary/Node.js)
- [Non-normative](https://developer.mozilla.org/en-US/docs/Glossary/Non-normative)
- [Nonce](https://developer.mozilla.org/en-US/docs/Glossary/Nonce)
- [Normative](https://developer.mozilla.org/en-US/docs/Glossary/Normative)
- [Null](https://developer.mozilla.org/en-US/docs/Glossary/Null)
- [Nullish value](https://developer.mozilla.org/en-US/docs/Glossary/Nullish_value)
- [Number](https://developer.mozilla.org/en-US/docs/Glossary/Number)
- [Object](https://developer.mozilla.org/en-US/docs/Glossary/Object)
- [Object reference](https://developer.mozilla.org/en-US/docs/Glossary/Object_reference)
- [OOP](https://developer.mozilla.org/en-US/docs/Glossary/OOP)
- [OpenGL](https://developer.mozilla.org/en-US/docs/Glossary/OpenGL)
- [OpenSSL](https://developer.mozilla.org/en-US/docs/Glossary/OpenSSL)
- [Opera browser](https://developer.mozilla.org/en-US/docs/Glossary/Opera_browser)
- [Operand](https://developer.mozilla.org/en-US/docs/Glossary/Operand)
- [Operator](https://developer.mozilla.org/en-US/docs/Glossary/Operator)
- [Origin](https://developer.mozilla.org/en-US/docs/Glossary/Origin)
- [OTA](https://developer.mozilla.org/en-US/docs/Glossary/OTA)
- [OWASP](https://developer.mozilla.org/en-US/docs/Glossary/OWASP)
- [P2P](https://developer.mozilla.org/en-US/docs/Glossary/P2P)
- [PAC](https://developer.mozilla.org/en-US/docs/Glossary/PAC)
- [Packet](https://developer.mozilla.org/en-US/docs/Glossary/Packet)
- [Page load time](https://developer.mozilla.org/en-US/docs/Glossary/Page_load_time)
- [Page prediction](https://developer.mozilla.org/en-US/docs/Glossary/Page_prediction)
- [Parameter](https://developer.mozilla.org/en-US/docs/Glossary/Parameter)
- [Parent object](https://developer.mozilla.org/en-US/docs/Glossary/Parent_object)
- [Parse](https://developer.mozilla.org/en-US/docs/Glossary/Parse)
- [Parser](https://developer.mozilla.org/en-US/docs/Glossary/Parser)
- [Payload body](https://developer.mozilla.org/en-US/docs/Glossary/Payload_body)
- [Payload header](https://developer.mozilla.org/en-US/docs/Glossary/Payload_header)
- [PDF](https://developer.mozilla.org/en-US/docs/Glossary/PDF)
- [Perceived performance](https://developer.mozilla.org/en-US/docs/Glossary/Perceived_performance)
- [Percent-encoding](https://developer.mozilla.org/en-US/docs/Glossary/Percent-encoding)
- [PHP](https://developer.mozilla.org/en-US/docs/Glossary/PHP)
- [Physical properties](https://developer.mozilla.org/en-US/docs/Glossary/Physical_properties)
- [Pixel](https://developer.mozilla.org/en-US/docs/Glossary/Pixel)
- [Placeholder names](https://developer.mozilla.org/en-US/docs/Glossary/Placeholder_names)
- [Plaintext](https://developer.mozilla.org/en-US/docs/Glossary/Plaintext)
- [Plugin](https://developer.mozilla.org/en-US/docs/Glossary/Plugin)
- [PNG](https://developer.mozilla.org/en-US/docs/Glossary/PNG)
- [Polyfill](https://developer.mozilla.org/en-US/docs/Glossary/Polyfill)
- [Polymorphism](https://developer.mozilla.org/en-US/docs/Glossary/Polymorphism)
- [POP3](https://developer.mozilla.org/en-US/docs/Glossary/POP3)
- [Port](https://developer.mozilla.org/en-US/docs/Glossary/Port)
- [Prefetch](https://developer.mozilla.org/en-US/docs/Glossary/Prefetch)
- [Preflight request](https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request)
- [Prerender](https://developer.mozilla.org/en-US/docs/Glossary/Prerender)
- [Presto](https://developer.mozilla.org/en-US/docs/Glossary/Presto)
- [Primitive](https://developer.mozilla.org/en-US/docs/Glossary/Primitive)
- [Principle of least privilege](https://developer.mozilla.org/en-US/docs/Glossary/Principle_of_least_privilege)
- [Privileged](https://developer.mozilla.org/en-US/docs/Glossary/Privileged)
- [Privileged code](https://developer.mozilla.org/en-US/docs/Glossary/Privileged_code)
- [Progressive enhancement](https://developer.mozilla.org/en-US/docs/Glossary/Progressive_enhancement)
- [Progressive web applications (*PWAs*)](https://developer.mozilla.org/en-US/docs/Glossary/Progressive_web_apps)
- [Promise](https://developer.mozilla.org/en-US/docs/Glossary/Promise)
- [Property](https://developer.mozilla.org/en-US/docs/Glossary/Property)
  - [Property (*CSS*)](https://developer.mozilla.org/en-US/docs/Glossary/Property/CSS)
  - [Property (*JavaScript*)](https://developer.mozilla.org/en-US/docs/Glossary/Property/JavaScript)
- [Protocol](https://developer.mozilla.org/en-US/docs/Glossary/Protocol)
- [Prototype](https://developer.mozilla.org/en-US/docs/Glossary/Prototype)
- [Prototype-based programming](https://developer.mozilla.org/en-US/docs/Glossary/Prototype-based_programming)
- [Proxy server](https://developer.mozilla.org/en-US/docs/Glossary/Proxy_server)
- [Pseudo-class](https://developer.mozilla.org/en-US/docs/Glossary/Pseudo-class)
- [Pseudo-element](https://developer.mozilla.org/en-US/docs/Glossary/Pseudo-element)
- [Pseudocode](https://developer.mozilla.org/en-US/docs/Glossary/Pseudocode)
- [Public-key cryptography](https://developer.mozilla.org/en-US/docs/Glossary/Public-key_cryptography)
- [Python](https://developer.mozilla.org/en-US/docs/Glossary/Python)
- [Quality values](https://developer.mozilla.org/en-US/docs/Glossary/Quality_values)
- [Quaternion](https://developer.mozilla.org/en-US/docs/Glossary/Quaternion)
- [QUIC](https://developer.mozilla.org/en-US/docs/Glossary/QUIC)
- [RAIL](https://developer.mozilla.org/en-US/docs/Glossary/RAIL)
- [Random Number Generator](https://developer.mozilla.org/en-US/docs/Glossary/Random_Number_Generator)
- [Raster image](https://developer.mozilla.org/en-US/docs/Glossary/Raster_image)
- [Rate limit](https://developer.mozilla.org/en-US/docs/Glossary/Rate_limit)
- [RDF](https://developer.mozilla.org/en-US/docs/Glossary/RDF)
- [Reading order](https://developer.mozilla.org/en-US/docs/Glossary/Reading_order)
- [Real User Monitoring (*RUM*)](https://developer.mozilla.org/en-US/docs/Glossary/Real_User_Monitoring)
- [Recursion](https://developer.mozilla.org/en-US/docs/Glossary/Recursion)
- [Reflow](https://developer.mozilla.org/en-US/docs/Glossary/Reflow)
- [Registrable domain](https://developer.mozilla.org/en-US/docs/Glossary/Registrable_domain)
- [Regular expression](https://developer.mozilla.org/en-US/docs/Glossary/Regular_expression)
- [Relying party](https://developer.mozilla.org/en-US/docs/Glossary/Relying_party)
- [Render-blocking](https://developer.mozilla.org/en-US/docs/Glossary/Render-blocking)
- [Repaint](https://developer.mozilla.org/en-US/docs/Glossary/Repaint)
- [Replaced elements](https://developer.mozilla.org/en-US/docs/Glossary/Replaced_elements)
- [Replay attack](https://developer.mozilla.org/en-US/docs/Glossary/Replay_attack)
- [Repo](https://developer.mozilla.org/en-US/docs/Glossary/Repo)
- [Reporting directive](https://developer.mozilla.org/en-US/docs/Glossary/Reporting_directive)
- [Representation header](https://developer.mozilla.org/en-US/docs/Glossary/Representation_header)
- [Request header](https://developer.mozilla.org/en-US/docs/Glossary/Request_header)
- [Resource Timing](https://developer.mozilla.org/en-US/docs/Glossary/Resource_Timing)
- [Response header](https://developer.mozilla.org/en-US/docs/Glossary/Response_header)
- [Responsive Web Design (*RWD*)](https://developer.mozilla.org/en-US/docs/Glossary/Responsive_Web_Design)
- [REST](https://developer.mozilla.org/en-US/docs/Glossary/REST)
- [RGB](https://developer.mozilla.org/en-US/docs/Glossary/RGB)
- [RIL](https://developer.mozilla.org/en-US/docs/Glossary/RIL)
- [Robots.txt](https://developer.mozilla.org/en-US/docs/Glossary/Robots.txt)
- [Round Trip Time (*RTT*)](https://developer.mozilla.org/en-US/docs/Glossary/Round_Trip_Time)
- [Router](https://developer.mozilla.org/en-US/docs/Glossary/Router)
- [RSS](https://developer.mozilla.org/en-US/docs/Glossary/RSS)
- [Rsync](https://developer.mozilla.org/en-US/docs/Glossary/Rsync)
- [RTCP (*RTP Control Protocol*)](https://developer.mozilla.org/en-US/docs/Glossary/RTCP)
- [RTF](https://developer.mozilla.org/en-US/docs/Glossary/RTF)
- [RTL (*Right to Left*)](https://developer.mozilla.org/en-US/docs/Glossary/RTL)
- [RTP (*Real-time Transport Protocol*) and SRTP (*Secure RTP*)](https://developer.mozilla.org/en-US/docs/Glossary/RTP)
- [RTSP: Real-time streaming protocol](https://developer.mozilla.org/en-US/docs/Glossary/RTSP)
- [Ruby](https://developer.mozilla.org/en-US/docs/Glossary/Ruby)
- [Safe](https://developer.mozilla.org/en-US/docs/Glossary/Safe)
  - [Safe (*HTTP Methods*)](https://developer.mozilla.org/en-US/docs/Glossary/Safe/HTTP)
- [Salt](https://developer.mozilla.org/en-US/docs/Glossary/Salt)
- [Same-origin policy](https://developer.mozilla.org/en-US/docs/Glossary/Same-origin_policy)
- [SCM](https://developer.mozilla.org/en-US/docs/Glossary/SCM)
- [Scope](https://developer.mozilla.org/en-US/docs/Glossary/Scope)
- [Screen reader](https://developer.mozilla.org/en-US/docs/Glossary/Screen_reader)
- [Script-supporting element](https://developer.mozilla.org/en-US/docs/Glossary/Script-supporting_element)
- [Scroll boundary](https://developer.mozilla.org/en-US/docs/Glossary/Scroll_boundary)
- [Scroll chaining](https://developer.mozilla.org/en-US/docs/Glossary/Scroll_chaining)
- [Scroll container](https://developer.mozilla.org/en-US/docs/Glossary/Scroll_container)
- [Scroll snap](https://developer.mozilla.org/en-US/docs/Glossary/Scroll_snap)
- [SCTP](https://developer.mozilla.org/en-US/docs/Glossary/SCTP)
- [SDK (*Software Development Kit*)](https://developer.mozilla.org/en-US/docs/Glossary/SDK)
- [SDP](https://developer.mozilla.org/en-US/docs/Glossary/SDP)
- [Search engine](https://developer.mozilla.org/en-US/docs/Glossary/Search_engine)
- [Secure context](https://developer.mozilla.org/en-US/docs/Glossary/Secure_context)
- [Secure Sockets Layer (*SSL*)](https://developer.mozilla.org/en-US/docs/Glossary/SSL)
- [Selector (*CSS*)](https://developer.mozilla.org/en-US/docs/Glossary/CSS_Selector)
- [Semantics](https://developer.mozilla.org/en-US/docs/Glossary/Semantics)
- [SEO](https://developer.mozilla.org/en-US/docs/Glossary/SEO)
- [Serializable object](https://developer.mozilla.org/en-US/docs/Glossary/Serializable_object)
- [Serialization](https://developer.mozilla.org/en-US/docs/Glossary/Serialization)
- [Server](https://developer.mozilla.org/en-US/docs/Glossary/Server)
- [Server Timing](https://developer.mozilla.org/en-US/docs/Glossary/Server_Timing)
- [Server-side rendering (*SSR*)](https://developer.mozilla.org/en-US/docs/Glossary/SSR)
- [Session hijacking](https://developer.mozilla.org/en-US/docs/Glossary/Session_hijacking)
- [SGML](https://developer.mozilla.org/en-US/docs/Glossary/SGML)
- [Shadow tree](https://developer.mozilla.org/en-US/docs/Glossary/Shadow_tree)
- [Shallow copy](https://developer.mozilla.org/en-US/docs/Glossary/Shallow_copy)
- [Shim](https://developer.mozilla.org/en-US/docs/Glossary/Shim)
- [Signature](https://developer.mozilla.org/en-US/docs/Glossary/Signature)
- [Signature (*functions*)](https://developer.mozilla.org/en-US/docs/Glossary/Signature_(functions))
- [Signature (*security*)](https://developer.mozilla.org/en-US/docs/Glossary/Signature_(security))
- [SIMD](https://developer.mozilla.org/en-US/docs/Glossary/SIMD)
- [SISD](https://developer.mozilla.org/en-US/docs/Glossary/SISD)
- [Site](https://developer.mozilla.org/en-US/docs/Glossary/Site)
- [Site map](https://developer.mozilla.org/en-US/docs/Glossary/Site_map)
- [SLD](https://developer.mozilla.org/en-US/docs/Glossary/SLD)
- [Sloppy mode](https://developer.mozilla.org/en-US/docs/Glossary/Sloppy_mode)
- [Slug](https://developer.mozilla.org/en-US/docs/Glossary/Slug)
- [Smoke test](https://developer.mozilla.org/en-US/docs/Glossary/Smoke_test)
- [SMPTE (*Society of Motion Picture and Television Engineers*)](https://developer.mozilla.org/en-US/docs/Glossary/SMPTE)
- [SMTP](https://developer.mozilla.org/en-US/docs/Glossary/SMTP)
- [Snake case](https://developer.mozilla.org/en-US/docs/Glossary/Snake_case)
- [Snap positions](https://developer.mozilla.org/en-US/docs/Glossary/Snap_positions)
- [SOAP](https://developer.mozilla.org/en-US/docs/Glossary/SOAP)
- [Social engineering](https://developer.mozilla.org/en-US/docs/Glossary/Social_engineering)
- [Source map](https://developer.mozilla.org/en-US/docs/Glossary/Source_map)
- [SPA (*Single-page application*)](https://developer.mozilla.org/en-US/docs/Glossary/SPA)
- [Specification](https://developer.mozilla.org/en-US/docs/Glossary/Specification)
- [Speculative parsing](https://developer.mozilla.org/en-US/docs/Glossary/Speculative_parsing)
- [Speed index](https://developer.mozilla.org/en-US/docs/Glossary/Speed_index)
- [SQL](https://developer.mozilla.org/en-US/docs/Glossary/SQL)
- [SQL injection](https://developer.mozilla.org/en-US/docs/Glossary/SQL_injection)
- [SRI](https://developer.mozilla.org/en-US/docs/Glossary/SRI)
- [Stacking context](https://developer.mozilla.org/en-US/docs/Glossary/Stacking_context)
- [State machine](https://developer.mozilla.org/en-US/docs/Glossary/State_machine)
- [Statement](https://developer.mozilla.org/en-US/docs/Glossary/Statement)
- [Static method](https://developer.mozilla.org/en-US/docs/Glossary/Static_method)
- [Static site generator (*SSG*)](https://developer.mozilla.org/en-US/docs/Glossary/SSG)
- [Static typing](https://developer.mozilla.org/en-US/docs/Glossary/Static_typing)
- [Sticky activation](https://developer.mozilla.org/en-US/docs/Glossary/Sticky_activation)
- [Strict mode](https://developer.mozilla.org/en-US/docs/Glossary/Strict_mode)
- [String](https://developer.mozilla.org/en-US/docs/Glossary/String)
- [Stringifier](https://developer.mozilla.org/en-US/docs/Glossary/Stringifier)
- [STUN](https://developer.mozilla.org/en-US/docs/Glossary/STUN)
- [Style origin](https://developer.mozilla.org/en-US/docs/Glossary/Style_origin)
- [Stylesheet](https://developer.mozilla.org/en-US/docs/Glossary/Stylesheet)
- [Submit button](https://developer.mozilla.org/en-US/docs/Glossary/Submit_button)
- [SVG](https://developer.mozilla.org/en-US/docs/Glossary/SVG)
- [SVN](https://developer.mozilla.org/en-US/docs/Glossary/SVN)
- [Symbol](https://developer.mozilla.org/en-US/docs/Glossary/Symbol)
- [Symmetric-key cryptography](https://developer.mozilla.org/en-US/docs/Glossary/Symmetric-key_cryptography)
- [Synchronous](https://developer.mozilla.org/en-US/docs/Glossary/Synchronous)
- [Syntax](https://developer.mozilla.org/en-US/docs/Glossary/Syntax)
- [Syntax error](https://developer.mozilla.org/en-US/docs/Glossary/Syntax_error)
- [Synthetic monitoring](https://developer.mozilla.org/en-US/docs/Glossary/Synthetic_monitoring)
- [Table grid box](https://developer.mozilla.org/en-US/docs/Glossary/Table_grid_box)
- [Table wrapper box](https://developer.mozilla.org/en-US/docs/Glossary/Table_wrapper_box)
- [Tag](https://developer.mozilla.org/en-US/docs/Glossary/Tag)
- [TCP](https://developer.mozilla.org/en-US/docs/Glossary/TCP)
- [TCP handshake](https://developer.mozilla.org/en-US/docs/Glossary/TCP_handshake)
- [TCP slow start](https://developer.mozilla.org/en-US/docs/Glossary/TCP_slow_start)
- [Telnet](https://developer.mozilla.org/en-US/docs/Glossary/Telnet)
- [Texel](https://developer.mozilla.org/en-US/docs/Glossary/Texel)
- [The Khronos Group](https://developer.mozilla.org/en-US/docs/Glossary/The_Khronos_Group)
- [Thread](https://developer.mozilla.org/en-US/docs/Glossary/Thread)
- [Three js](https://developer.mozilla.org/en-US/docs/Glossary/Three_js)
- [Throttle](https://developer.mozilla.org/en-US/docs/Glossary/Throttle)
- [Time to First Byte (*TTFB*)](https://developer.mozilla.org/en-US/docs/Glossary/Time_to_first_byte)
- [Time to Interactive (*TTI*)](https://developer.mozilla.org/en-US/docs/Glossary/Time_to_interactive)
- [TLD](https://developer.mozilla.org/en-US/docs/Glossary/TLD)
- [TOFU](https://developer.mozilla.org/en-US/docs/Glossary/TOFU)
- [Top layer](https://developer.mozilla.org/en-US/docs/Glossary/Top_layer)
- [Transient activation](https://developer.mozilla.org/en-US/docs/Glossary/Transient_activation)
- [Transport Layer Security (*TLS*)](https://developer.mozilla.org/en-US/docs/Glossary/TLS)
- [Tree shaking](https://developer.mozilla.org/en-US/docs/Glossary/Tree_shaking)
- [Trident](https://developer.mozilla.org/en-US/docs/Glossary/Trident)
- [Truthy](https://developer.mozilla.org/en-US/docs/Glossary/Truthy)
- [TTL](https://developer.mozilla.org/en-US/docs/Glossary/TTL)
- [TURN](https://developer.mozilla.org/en-US/docs/Glossary/TURN)
- [Type](https://developer.mozilla.org/en-US/docs/Glossary/Type)
- [Type coercion](https://developer.mozilla.org/en-US/docs/Glossary/Type_coercion)
- [Type conversion](https://developer.mozilla.org/en-US/docs/Glossary/Type_conversion)
- [TypeScript](https://developer.mozilla.org/en-US/docs/Glossary/TypeScript)
- [UAAG](https://developer.mozilla.org/en-US/docs/Glossary/UAAG)
- [UDP (*User Datagram Protocol*)](https://developer.mozilla.org/en-US/docs/Glossary/UDP)
- [UI](https://developer.mozilla.org/en-US/docs/Glossary/UI)
- [Undefined](https://developer.mozilla.org/en-US/docs/Glossary/Undefined)
- [Unicode](https://developer.mozilla.org/en-US/docs/Glossary/Unicode)
- [Unix time](https://developer.mozilla.org/en-US/docs/Glossary/Unix_time)
- [URI](https://developer.mozilla.org/en-US/docs/Glossary/URI)
- [URL](https://developer.mozilla.org/en-US/docs/Glossary/URL)
- [URN](https://developer.mozilla.org/en-US/docs/Glossary/URN)
- [Usenet](https://developer.mozilla.org/en-US/docs/Glossary/Usenet)
- [User agent](https://developer.mozilla.org/en-US/docs/Glossary/User_agent)
- [UTF-8](https://developer.mozilla.org/en-US/docs/Glossary/UTF-8)
- [UTF-16](https://developer.mozilla.org/en-US/docs/Glossary/UTF-16)
- [UUID](https://developer.mozilla.org/en-US/docs/Glossary/UUID)
- [UX](https://developer.mozilla.org/en-US/docs/Glossary/UX)
- [Validator](https://developer.mozilla.org/en-US/docs/Glossary/Validator)
- [Value](https://developer.mozilla.org/en-US/docs/Glossary/Value)
- [Variable](https://developer.mozilla.org/en-US/docs/Glossary/Variable)
- [Vendor prefix](https://developer.mozilla.org/en-US/docs/Glossary/Vendor_prefix)
- [Viewport](https://developer.mozilla.org/en-US/docs/Glossary/Viewport)
- [Visual viewport](https://developer.mozilla.org/en-US/docs/Glossary/Visual_viewport)
- [Void element](https://developer.mozilla.org/en-US/docs/Glossary/Void_element)
- [VoIP](https://developer.mozilla.org/en-US/docs/Glossary/VoIP)
- [W3C](https://developer.mozilla.org/en-US/docs/Glossary/W3C)
- [WAI](https://developer.mozilla.org/en-US/docs/Glossary/WAI)
- [WCAG](https://developer.mozilla.org/en-US/docs/Glossary/WCAG)
- [Web performance](https://developer.mozilla.org/en-US/docs/Glossary/Web_performance)
- [Web server](https://developer.mozilla.org/en-US/docs/Glossary/Web_server)
- [Web standards](https://developer.mozilla.org/en-US/docs/Glossary/Web_standards)
- [WebAssembly](https://developer.mozilla.org/en-US/docs/Glossary/WebAssembly)
- [WebDAV](https://developer.mozilla.org/en-US/docs/Glossary/WebDAV)
- [WebExtensions](https://developer.mozilla.org/en-US/docs/Glossary/WebExtensions)
- [WebGL](https://developer.mozilla.org/en-US/docs/Glossary/WebGL)
- [WebIDL](https://developer.mozilla.org/en-US/docs/Glossary/WebIDL)
- [WebKit](https://developer.mozilla.org/en-US/docs/Glossary/WebKit)
- [WebM](https://developer.mozilla.org/en-US/docs/Glossary/WebM)
- [WebP](https://developer.mozilla.org/en-US/docs/Glossary/WebP)
- [WebRTC](https://developer.mozilla.org/en-US/docs/Glossary/WebRTC)
- [WebSockets](https://developer.mozilla.org/en-US/docs/Glossary/WebSockets)
- [WebVTT](https://developer.mozilla.org/en-US/docs/Glossary/WebVTT)
- [WHATWG](https://developer.mozilla.org/en-US/docs/Glossary/WHATWG)
- [Whitespace](https://developer.mozilla.org/en-US/docs/Glossary/Whitespace)
- [WindowProxy](https://developer.mozilla.org/en-US/docs/Glossary/WindowProxy)
- [World Wide Web](https://developer.mozilla.org/en-US/docs/Glossary/World_Wide_Web)
- [Wrapper](https://developer.mozilla.org/en-US/docs/Glossary/Wrapper)
- [XFormsDeprecated](https://developer.mozilla.org/en-US/docs/Glossary/XFormsDeprecated)
- [XHTML](https://developer.mozilla.org/en-US/docs/Glossary/XHTML)
- [XInclude](https://developer.mozilla.org/en-US/docs/Glossary/XInclude)
- [XLink](https://developer.mozilla.org/en-US/docs/Glossary/XLink)
- [XML](https://developer.mozilla.org/en-US/docs/Glossary/XML)
- [XMLHttpRequest (*XHR*)](https://developer.mozilla.org/en-US/docs/Glossary/XMLHttpRequest_(XHR))
- [XPath](https://developer.mozilla.org/en-US/docs/Glossary/XPath)
- [XQuery](https://developer.mozilla.org/en-US/docs/Glossary/XQuery)
- [XSLT](https://developer.mozilla.org/en-US/docs/Glossary/XSLT)
- [Zstandard compression](https://developer.mozilla.org/en-US/docs/Glossary/Zstandard_compression)
