Web Design & Development Glossary A-Z (2026)

A

A/B Test: Showing two versions (A, B) to users randomly to measure which converts better.

Accessibility: Usable by everyone including disabled users. WCAG standard.

Above the Fold: Portion visible without scrolling.

API: Application Programming Interface — how software talks to software.

ARIA: Accessible Rich Internet Applications — HTML attributes for screen readers.

B

Backend: Server-side code. Database, business logic, APIs.

Bandwidth: Data volume per second a link can carry.

Bounce Rate: % of visitors viewing one page then leaving.

Breadcrumb: Hierarchical navigation (Home → Products → Phone).

Breakpoint: Style change thresholds for responsive design.

C

Cache: Stored frequently-used data for fast access.

Canonical URL: The "main" URL among duplicates. Critical for SEO.

CDN: Content Delivery Network — global cache servers.

CMS: Content Management System.

CLS: Cumulative Layout Shift — content-shift measure during load.

Headless CMS: CMS without coupled frontend.

Core Web Vitals: Google''s performance metrics (LCP, INP, CLS).

CRM: Customer Relationship Management.

CSR: Client-Side Rendering — render in browser.

D

Domain: Site address like example.com.

DNS: Domain Name System — name → IP.

DOM: Document Object Model — HTML tree structure.

DevOps: Unified development + operations practice.

Docker: Application packaging via containers.

E

Edge Computing: Work done on servers near the user.

ERP: Enterprise Resource Planning.

Event: User interaction (click, scroll, submit).

Evergreen Content: Content that retains value over time.

F

Favicon: Small icon shown in browser tab.

FID: First Input Delay — replaced by INP in 2024.

FCP: First Contentful Paint.

Framework: Scaffolding to speed dev (React, Vue, Laravel).

Frontend: What users see.

FTP: File Transfer Protocol.

G

Git: Version control system.

GA4: Google Analytics 4.

GDPR: EU data protection regulation.

GraphQL: API query language alternative to REST.

H

Headless: Backend without coupled frontend.

Hosting: Site-hosting service.

Hreflang: Language/region tag for multilingual sites.

HTTPS: Encrypted HTTP via SSL/TLS.

Hydration: React attaching to SSR HTML.

I

INP: Interaction to Next Paint — response-time metric.

ISR: Incremental Static Regeneration — Next.js smart caching.

IP: Internet Protocol address.

J

JavaScript: Web''s programming language.

JSON: JavaScript Object Notation.

JSON-LD: Structured data format for schema.org.

JWT: JSON Web Token for authentication.

K

Keyword: SEO target term.

L

LCP: Largest Contentful Paint.

Lazy Loading: Loading images/resources on demand.

Landing Page: Campaign-focused destination page.

LTV: Customer lifetime value.

M

Markup: HTML markup language.

Meta Tag: Info tags in document head.

Middleware: Layer running before request handlers.

MVC: Model-View-Controller architecture.

N

Nameserver: Authoritative DNS server for a domain.

Next.js: React-based full-stack framework.

Node.js: JavaScript runtime on server.

O

OG Image: Open Graph social-share image.

ORM: Object-Relational Mapping (Prisma, TypeORM).

Open Source: Openly licensed code.

P

PWA: Progressive Web App.

PageSpeed Insights: Google''s speed measurement tool.

Ping: Server latency test.

R

RAG: Retrieval-Augmented Generation.

React: Frontend library from Facebook.

Redis: Fast in-memory database.

Responsive: Adapts to screen sizes.

REST: API architectural style.

ROAS: Return on Ad Spend.

ROI: Return on Investment.

S

SaaS: Software as a Service.

Schema.org: Structured data standard.

SEO: Search Engine Optimization.

SERP: Search Engine Results Page.

Sitemap: XML listing of pages for search engines.

SPA: Single Page Application.

SSL/TLS: Encryption protocols.

SSG: Static Site Generation.

SSR: Server-Side Rendering.

SLA: Service Level Agreement.

T

Tailwind: Utility-first CSS framework.

TTFB: Time To First Byte.

TTL: Time To Live (cache expiry).

U

UI: User Interface.

UX: User Experience.

UTM: Marketing tracking parameters.

V

VPS: Virtual Private Server.

W

WAF: Web Application Firewall.

WCAG: Web accessibility guidelines.

WebP / AVIF: Modern image formats.

Webhook: Event-based HTTP notification.

WebSocket: Persistent bidirectional connection.

WordPress: Most widespread CMS.

X - Y - Z

XML: Extensible Markup Language.

YAML: Human-readable configuration format.

Zero Trust: Security model that trusts no network.

FAQs

Can I download this glossary?

Yes, as PDF from our downloads page.

How often updated?

Twice a year, with new terms added.

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