Website glossary

Website projects come with a lot of jargon, and it can be hard to follow a conversation with a designer, developer or hosting company when every other word is an acronym. This glossary explains the terms you are most likely to run into during a redesign in plain English, along with why each one matters for a business website. Use the related terms under each entry to explore connected ideas.

301 redirect: A 301 redirect is a server instruction that tells browsers and search engines a page has moved permanently to a new address, and sends visitors there automatically. Search engines treat it as a strong signal that the new address should replace the old one in their results. During a redesign, setting up 301 redirects from every old page address to its closest new equivalent is one of the most important steps for keeping existing search traffic, bookmarks and links working.; Related:Redirect 404 error URL SEO (search engine optimization)
404 error: A 404 error is the response a web server gives when someone requests a page that does not exist, usually shown as a "page not found" message. It often appears after pages are deleted or renamed without a redirect, or when a link contains a typo. A few 404s for pages that genuinely no longer exist are normal, but broken links to important pages frustrate visitors and waste the value of links pointing to your site, so a helpful custom 404 page and careful redirects are worth the effort.; Related:301 redirect Redirect URL Backlink
Accessibility: Web accessibility means designing and building a website so that people with disabilities can perceive, understand, navigate and use it, including people who use screen readers, keyboard-only navigation, captions or magnification. It covers things like readable color contrast, descriptive image text, clear headings and forms that work without a mouse. An accessible site reaches more customers, tends to be easier for everyone to use, and reduces legal risk in places where accessibility is required by law.; Related:WCAG (Web Content Accessibility Guidelines)Alt text UX (user experience)Web standards
Alt text: Alt text, short for alternative text, is a short written description of an image added to the page's HTML through the image's alt attribute. Screen readers read it aloud to people who cannot see the image, browsers display it if the image fails to load, and search engines use it to understand what the image shows. Good alt text describes the purpose of the image in context, while purely decorative images should be given an empty alt attribute so assistive technology skips them.; Related:Accessibility HTML SEO (search engine optimization)WCAG (Web Content Accessibility Guidelines)
Analytics: Website analytics is the collection and reporting of data about how people find and use a website, such as how many visits it gets, which pages are viewed, where visitors come from and which actions they complete. It is usually gathered by a small script added to every page, with Google Analytics being one widely used example. Analytics lets a business measure whether its site is producing leads or sales and compare performance before and after a redesign, but it often relies on cookies, which can bring privacy and consent obligations.; Related:Cookie Privacy policy Search Console Landing page
API: An API, or application programming interface, is a defined way for one piece of software to request information or actions from another. Websites use APIs behind the scenes to show maps, take payments, display booking calendars, pull in reviews or send form submissions to a CRM. For a business, APIs are what let a website connect with the other tools it already relies on, though each connection is something that needs to be maintained when either system changes.; Related:JavaScript Front end and back end Server Plugin
Backlink: A backlink is a link from another website that points to a page on your site. Search engines use links as one of many signals for discovering pages and judging how relevant and trustworthy they are, so backlinks from reputable, related websites can help a page's visibility. Buying links or joining link schemes violates search engine spam policies, and when pages move during a redesign, redirects are needed so existing backlinks still lead somewhere useful.; Related:SEO (search engine optimization)301 redirect 404 error URL
Bandwidth: Strictly speaking, bandwidth is the maximum rate at which data can travel over a connection, but hosting companies often use the word to mean the total amount of data a site is allowed to send to visitors each month, also called data transfer. Every page view uses some of it, and large images and videos use the most. Knowing your plan's limits helps you avoid slowdowns, overage charges or a suspended site if traffic suddenly grows.; Related:Web hosting CDN (content delivery network)Page speed Server
Browser: A web browser is the application people use to visit websites, such as Chrome, Safari, Firefox or Edge. It downloads a page's HTML, CSS, JavaScript, images and fonts and assembles them into the page you see and interact with. Different browsers and devices can display the same page slightly differently, so a new or redesigned site should be tested on the browsers your customers actually use.; Related:HTML CSS JavaScript Web standards
Cache: A cache is a temporary stored copy of files or data kept so they can be delivered faster the next time they are needed. Browsers, web servers, plugins and content delivery networks all keep caches, which can make a site much quicker for returning visitors. The trade-off is that after an update, some people may briefly see older versions of pages or files until the cache is cleared or expires, which is a common source of confusion right after a redesign launches.; Related:CDN (content delivery network)Page speed Browser Server
Call to action (CTA): A call to action is a prompt that invites the visitor to take a specific next step, such as "Request a quote", "Call now" or "Book an appointment", usually presented as a button or a prominent link. Clear calls to action turn a website from an online brochure into a tool that generates leads and sales. Good ones use specific wording, stand out visually and appear where a visitor is ready to act, without crowding the page with competing requests.; Related:Landing page UX (user experience)UI (user interface)Analytics
Canonical URL: A canonical URL is the address you want search engines to treat as the main version of a page when the same or very similar content can be reached at more than one address, for example with and without tracking parameters. It is usually indicated with a canonical link element in the page's HTML, which search engines treat as a strong hint rather than a strict command. Getting canonicals right prevents ranking signals from being split across duplicate addresses, and they should be checked after a redesign changes the site's URL structure.; Related:URL SEO (search engine optimization)301 redirect XML sitemap
CDN (content delivery network): A content delivery network is a group of servers spread across many locations that store copies of a website's files and deliver them from a location close to each visitor. This shortens the distance data has to travel, which usually makes pages load faster and helps a site cope with traffic spikes. Many CDNs also add security features such as protection against denial-of-service attacks, which makes them useful even for small business sites.; Related:Cache Page speed Web hosting Server
CMS (content management system): A content management system is software that lets people create, edit and publish website content through an editing screen instead of writing code. WordPress is a well-known example, and many other open-source and hosted systems exist. Choosing a CMS is one of the biggest decisions in a redesign, because it determines how easily your team can update the site, what features are available and how much ongoing maintenance the site will need.; Related:WordPress Plugin Front end and back end Web hosting
CNAME record: A CNAME record, short for canonical name record, is a DNS setting that makes one hostname an alias of another hostname, so it follows wherever that other name points. It is commonly used to connect a subdomain, such as the www version of a site or a store subdomain, to a service run by a hosting platform. Standard DNS rules do not allow a CNAME at the bare root of a domain, although some DNS providers offer workarounds, so the exact setup depends on your provider.; Related:DNS (Domain Name System)Subdomain Domain name MX record
Cookie: A cookie is a small piece of data that a website asks the visitor's browser to store and send back on later requests. Cookies keep people logged in, remember shopping cart contents and preferences, and are also used by analytics and advertising tools to recognize returning visitors. Because some cookies can track people, privacy laws in many regions require businesses to explain their cookie use and, in some places, ask for consent before setting non-essential cookies.; Related:Privacy policy Analytics Browser HTTP and HTTPS
Core Web Vitals: Core Web Vitals are a set of three measurements Google uses to describe a page's real-world user experience: Largest Contentful Paint for loading speed, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability. They are measured from data collected from real visitors, and a page is considered good when at least 75 percent of visits meet the recommended thresholds. Google uses them as part of its page experience signals in search, and improving them generally makes a site feel faster and more pleasant to use.; Related:Largest Contentful Paint (LCP)Interaction to Next Paint (INP)Cumulative Layout Shift (CLS)Page speed
CSS: CSS, or Cascading Style Sheets, is the language that controls how web pages look, including colors, fonts, spacing, layout and how the design adapts to different screen sizes. HTML provides the structure and content, and CSS provides the presentation. Well-organized CSS makes a site look consistent from page to page and makes future design changes much easier, while bloated or unused CSS can slow pages down.; Related:HTML Responsive design Web fonts Front end and back end
Cumulative Layout Shift (CLS): Cumulative Layout Shift is a Core Web Vitals metric that measures how much the visible content of a page unexpectedly jumps around while someone is using it. Shifts are often caused by images or ads without reserved space, late-loading fonts, or banners inserted above existing content. A score of 0.1 or less is considered good, and keeping it low prevents frustrating mistakes like tapping the wrong button because the page moved.; Related:Core Web Vitals Largest Contentful Paint (LCP)Interaction to Next Paint (INP)Web fonts
DNS (Domain Name System): The Domain Name System is the internet's directory service: it translates human-friendly domain names into the numeric IP addresses computers use to find each other. A domain's DNS records control where its website, email and other services live. DNS changes are a routine part of launching a redesigned site or switching hosts, and because records are cached for a set time, changes can take minutes to hours to reach everyone.; Related:Domain name IP address CNAME record MX record
Domain name: A domain name is the human-readable address of a website, made up of a name and an extension such as .com, .org or a country code. You do not buy a domain outright; you register the right to use it for a period and renew it, typically every year or every few years. Your domain is a core business asset tied to your brand, website and email, so it should be registered in an account the business controls and set to renew automatically.; Related:Domain registrar DNS (Domain Name System)URL Subdomain
Domain registrar: A domain registrar is a company authorized to register domain names on your behalf and manage their renewal. The registrar is where you control the domain's ownership details, renewal settings and, often, its DNS settings or which DNS provider it uses. Many businesses run into trouble when a former employee or web vendor registered the domain in their own name, so it is worth confirming who controls the registrar account before starting a redesign.; Related:Domain name DNS (Domain Name System)Web hosting Email authentication (SPF, DKIM, DMARC)
Email authentication (SPF, DKIM, DMARC): SPF, DKIM and DMARC are three DNS-based standards that help prove email sent from your domain is legitimate. SPF lists the servers allowed to send mail for the domain, DKIM adds a cryptographic signature that receivers can check, and DMARC tells receiving mail systems what to do with messages that fail these checks and can send you reports about them. Together they reduce spoofing and help your messages reach inboxes, and major mailbox providers now require them for senders of large volumes of email.; Related:DNS (Domain Name System)MX record Domain name Domain registrar
Favicon: A favicon is the small icon associated with a website that appears in browser tabs, bookmarks, history lists and, in Google, next to the site's listing in search results. It is usually a simplified version of the company logo. Although small, a clear favicon helps people recognize your site among many open tabs and search results, and it is easy to forget during a redesign.; Related:Browser HTML UI (user interface)SEO (search engine optimization)
Front end and back end: The front end is everything a visitor sees and interacts with in the browser, built with HTML, CSS and JavaScript. The back end is the behind-the-scenes part that runs on a server, such as the database, the CMS editing screens, form processing and user accounts. Knowing the difference helps when talking with developers, because a redesign might change only the front end, only the back end, or both, with very different costs.; Related:HTML CSS JavaScript Server
HTML: HTML, or HyperText Markup Language, is the standard language used to structure content on the web, marking up headings, paragraphs, links, images, lists and forms. Browsers read HTML to build a page, and search engines and assistive technologies read it to understand the content. Clean, meaningful HTML that uses the right element for each job improves accessibility and search visibility and makes a site easier to maintain.; Related:CSS JavaScript Web standards Accessibility
HTTP and HTTPS: HTTP is the protocol browsers and web servers use to request and deliver web pages, and HTTPS is the secure version that encrypts the connection using TLS. Encryption protects information like form submissions and passwords from being read or altered in transit and confirms the visitor is talking to the real site. Modern browsers warn visitors when a page is not secure, and Google has used HTTPS as a ranking signal, so every business site should use HTTPS on every page.; Related:SSL/TLS certificate URL Server Browser
Interaction to Next Paint (INP): Interaction to Next Paint is a Core Web Vitals metric that measures how quickly a page visibly responds when someone clicks, taps or presses a key, looking at interactions throughout the whole visit. It replaced the older First Input Delay metric in March 2024. An INP of 200 milliseconds or less is considered good, and poor scores are often caused by heavy JavaScript, which can make menus, buttons and forms feel sluggish.; Related:Core Web Vitals Largest Contentful Paint (LCP)Cumulative Layout Shift (CLS)JavaScript
IP address: An IP address is a numeric label that identifies a device or server on a network, much like a street address for computers. Every website is ultimately reached through the IP address of the server hosting it, which DNS looks up from the domain name. Both the older IPv4 format and the newer, longer IPv6 format are in use, and you may need your host's IP addresses when changing DNS settings during a site move.; Related:DNS (Domain Name System)Server Domain name Web hosting
JavaScript: JavaScript is the programming language that runs in web browsers to make pages interactive, powering things like menus, image sliders, form validation, live chat and maps. It works alongside HTML for structure and CSS for presentation. Used thoughtfully it improves the experience, but too much JavaScript, often from third-party scripts and plugins, is a common cause of slow, unresponsive pages.; Related:HTML CSS Interaction to Next Paint (INP)API
Landing page: In marketing, a landing page is a page designed around a single goal, such as collecting a sign-up or a quote request, and is often the destination for an ad, email or promotion. More loosely, the term can also mean whatever page a visitor first arrives on. Focused landing pages with one clear call to action and messaging that matches the ad that sent the visitor usually convert better than sending everyone to the home page.; Related:Call to action (CTA)Analytics UX (user experience)SEO (search engine optimization)
Largest Contentful Paint (LCP): Largest Contentful Paint is a Core Web Vitals metric that measures how long it takes for the biggest image or block of text visible on screen to appear after a visitor starts loading a page. It is a practical stand-in for when the main content seems loaded to the person waiting. An LCP of 2.5 seconds or less is considered good, and common fixes include optimizing large hero images, using faster hosting or a CDN, and reducing render-blocking files.; Related:Core Web Vitals Interaction to Next Paint (INP)Cumulative Layout Shift (CLS)Page speed
Meta description: A meta description is a short summary of a page placed in its HTML that search engines may show as the snippet text under the page title in search results. Google sometimes writes its own snippet from the page content instead, and the meta description is not a direct ranking factor. A clear, accurate and unique description for each important page can still encourage more people to click through to your site.; Related:Title tag SEO (search engine optimization)HTML Search Console
Mobile-first design: Mobile-first design is an approach where a website is planned and built for small phone screens first and then expanded for tablets and desktops. It forces decisions about what content and actions matter most, since there is little room for clutter. It also matches how search works today, because Google primarily uses the mobile version of a site's content for indexing and ranking.; Related:Responsive design UX (user experience)Page speed Navigation menu
MX record: An MX record, short for mail exchange record, is a DNS setting that tells other mail systems which servers accept email for your domain. Each MX record has a priority number so mail can fall back to backup servers in order. When a website moves to new hosting or DNS changes during a redesign, MX records must be carried over correctly or the business can stop receiving email.; Related:DNS (Domain Name System)Email authentication (SPF, DKIM, DMARC)CNAME record Domain name
Navigation menu: The navigation menu is the set of links, usually across the top of a page or behind a menu icon on phones, that lets visitors move between the main sections of a website. Its labels and structure reflect how the site is organized. Clear, predictable navigation with plain-language labels helps visitors find what they came for quickly and helps search engines understand which pages are most important.; Related:UX (user experience)UI (user interface)Visual sitemap Mobile-first design
Page speed: Page speed is a general term for how quickly a web page loads and becomes usable for visitors. It depends on factors such as image sizes, the amount of code, the number of third-party scripts, hosting performance and the visitor's device and connection. Faster pages keep visitors from giving up and leaving, and speed-related measurements such as Core Web Vitals are part of how Google evaluates page experience.; Related:Core Web Vitals CDN (content delivery network)Cache Web hosting
Plugin: A plugin is an add-on that extends what a website platform can do, such as adding contact forms, online booking, search engine settings or e-commerce features to a CMS. Plugins let businesses add features without custom development. Each one is also code from a third party that needs regular updates, can slow the site down and can introduce security holes if abandoned, so it pays to install only what you actually need.; Related:CMS (content management system)WordPress API Page speed
Privacy policy: A privacy policy is a page that explains what personal information a website collects, how it is used and shared, and what choices visitors have. Laws in many places, as well as the terms of many analytics and advertising services, require a privacy policy when a site collects personal data through forms, cookies or tracking tools. It should accurately reflect what your site actually does and be reviewed whenever you add new tools during a redesign.; Related:Cookie Analytics Accessibility HTTP and HTTPS
Redirect: A redirect automatically sends a visitor or search engine from one URL to another. Permanent redirects, such as 301 and 308, tell search engines the move is lasting, while temporary ones, such as 302 and 307, signal that the original address will return. Server-side redirects are the most reliable kind, and a redesign usually needs a complete redirect map so that old page addresses lead to the right new pages instead of error pages.; Related:301 redirect 404 error URL Canonical URL
Responsive design: Responsive design is a way of building websites so the same pages automatically adapt their layout to fit any screen size, from phones to large monitors. It uses flexible layouts, flexible images and CSS rules that change the design at different widths. Responsive design means maintaining one site instead of separate desktop and mobile versions, and it is the approach Google recommends for mobile-friendly sites.; Related:Mobile-first design CSS UX (user experience)UI (user interface)
robots.txt: Robots.txt is a plain text file placed at the root of a website that tells search engine crawlers which parts of the site they may or may not crawl. Reputable crawlers follow it, but it is not a security tool and does not reliably keep a page out of search results, since a blocked page can still be indexed if other sites link to it. A classic redesign mistake is launching the new site with the staging site's block-everything robots.txt still in place, which can quietly cut off search traffic.; Related:XML sitemap SEO (search engine optimization)Staging site Search Console
Search Console: Google Search Console is a free service from Google that shows how a website performs in Google Search, including which searches bring visitors, which pages are indexed, and any crawling, security or usability problems Google has found. Site owners can also use it to submit sitemaps and request that updated pages be recrawled. It is especially valuable around a redesign launch for spotting broken pages and indexing problems quickly; other search engines, such as Bing, offer similar webmaster tools.; Related:SEO (search engine optimization)XML sitemap Analytics Core Web Vitals
SEO (search engine optimization): Search engine optimization is the practice of improving a website so search engines can find, understand and show its pages to people searching for relevant topics. It includes technical work such as site speed and crawlability, on-page work such as useful content, titles and headings, and earning links from other reputable sites. Because unpaid search traffic is a major source of customers for many businesses, a redesign that ignores SEO can undo years of progress almost overnight.; Related:Title tag Meta description Backlink Search Console
Server: A server is a computer, or a virtual computer, that stores a website's files and software and responds to requests from visitors' browsers by sending back pages and data. Servers can also run databases, process forms and send email. The power, location and maintenance of the server hosting your site directly affect its speed, reliability and security.; Related:Web hosting IP address Uptime Front end and back end
SSL/TLS certificate: An SSL/TLS certificate is a digital file issued by a trusted certificate authority that proves a website's identity and enables the encrypted HTTPS connection between the site and its visitors. TLS is the modern protocol; SSL is its outdated predecessor, but the older name has stuck. Certificates expire and must be renewed, and maximum certificate lifetimes are being shortened in stages, so automatic renewal is the safest way to avoid browser security warnings.; Related:HTTP and HTTPS Web hosting Domain name Server
Staging site: A staging site is a private copy of a website used to build and test changes before they go live. It lets a business review a redesign, new features or updates without affecting real visitors. Staging sites should be password-protected or hidden from search engines so they are not indexed as duplicate content, and those blocks must be removed from the live site at launch.; Related:robots.txt Wireframe Web hosting Subdomain
Structured data (schema markup): Structured data is code added to a page that labels its information in a standardized format, such as a business's name, address, opening hours, products, prices, events or reviews. Most structured data uses the shared Schema.org vocabulary, and Google recommends the JSON-LD format for adding it. It helps search engines understand the page and can make it eligible for enhanced search listings called rich results, although adding it does not guarantee they will appear.; Related:SEO (search engine optimization)HTML Search Console Title tag
Subdomain: A subdomain is an extra name added in front of a main domain to create a separate address, commonly used for a blog, online store, help center or customer portal. The familiar www prefix is itself technically a subdomain. Subdomains are configured in DNS and can point to entirely different services, which is convenient, but they need to be included in your redirect, analytics and security planning during a redesign.; Related:Domain name DNS (Domain Name System)CNAME record URL
Title tag: The title tag is an HTML element that gives each page its title, shown in the browser tab and often used by search engines as the clickable headline in search results. Search engines may sometimes rewrite the displayed title, but the title tag remains one of the clearest ways to tell them what a page is about. Each page should have a unique, descriptive title, and redesigns sometimes accidentally replace carefully written titles with generic ones.; Related:Meta description SEO (search engine optimization)HTML Structured data (schema markup)
UI (user interface): The user interface is everything a person sees and interacts with on a website, including buttons, menus, forms, typography, colors and icons. UI design focuses on making those elements clear, consistent and visually appealing. A polished, consistent interface builds trust in a business and makes key actions, such as contacting you or buying, easy to spot.; Related:UX (user experience)Call to action (CTA)Navigation menu Wireframe
Uptime: Uptime is the share of time a website is online and reachable, usually expressed as a percentage. Small differences matter: 99.9 percent uptime still allows close to nine hours of downtime over a year. Hosting plans often advertise an uptime guarantee, and an uptime monitoring service can alert you when your site goes down so it can be fixed before customers notice.; Related:Web hosting Server CDN (content delivery network)Bandwidth
URL: A URL, or Uniform Resource Locator, is the full web address of a specific page or file, including the protocol (such as https), the domain name and the path to the page. Clean, readable URLs help visitors and search engines understand what a page is about before they open it. Changing URLs during a redesign is sometimes necessary, but every changed address needs a redirect from the old one.; Related:Domain name HTTP and HTTPS 301 redirect Canonical URL
UX (user experience): User experience describes how easy, efficient and satisfying it is for people to use a website and accomplish what they came to do. UX work looks at the whole journey, including content, page structure, navigation, speed and accessibility, often informed by research or testing with real users. Good UX turns more visitors into customers and reduces frustrated calls and emails, which is why it is usually the main goal behind a redesign.; Related:UI (user interface)Accessibility Wireframe Navigation menu
Visual sitemap: A visual sitemap is a diagram, usually drawn as a tree, that shows all the pages of a website and how they are grouped and linked. It is a planning tool for people rather than a file for search engines. Creating one early in a redesign helps everyone agree on the site's structure and navigation before design and content work begins, and it makes it easier to spot old pages that need redirects.; Related:XML sitemap Wireframe Navigation menu UX (user experience)
WCAG (Web Content Accessibility Guidelines): The Web Content Accessibility Guidelines are the internationally recognized standard for web accessibility, published by the World Wide Web Consortium (W3C). They set out testable success criteria at three levels, A, AA and AAA, with WCAG 2.2 being the current version. Level AA is the target most commonly referenced in laws, regulations and contracts, so it is a sensible benchmark for any business website.; Related:Accessibility Alt text Web standards UX (user experience)
Web fonts: Web fonts are typefaces that a website downloads and uses to display its text, rather than relying only on the fonts already installed on a visitor's device. They allow a site's typography to match its brand. Each font file adds to the page weight, and fonts that load late can delay text or cause it to shift, so a sensible setup uses only the styles needed, loads them efficiently and makes sure the font's license allows web use.; Related:CSS Cumulative Layout Shift (CLS)Page speed UI (user interface)
Web hosting: Web hosting is the service of storing a website's files on internet-connected servers so people can visit it. Common types include shared hosting, virtual private servers, dedicated servers, cloud hosting, managed hosting for a specific CMS, and static hosting for sites made of prebuilt pages. The hosting you choose affects your site's speed, uptime, security and maintenance responsibilities, so it should match the site's needs rather than simply being the cheapest option.; Related:Server Uptime Bandwidth CDN (content delivery network)
Web standards: Web standards are the shared technical specifications that define how web technologies such as HTML, CSS, JavaScript and HTTP should work, developed by organizations including the W3C, WHATWG, Ecma International and the IETF. They are what allow a site to work across different browsers and devices. Building to standards makes a site more durable, accessible and easier for future developers to maintain.; Related:HTML CSS Browser WCAG (Web Content Accessibility Guidelines)
Wireframe: A wireframe is a simple, usually black-and-white layout sketch of a web page that shows where content, navigation, images and buttons will go, without final colors, images or styling. It focuses the conversation on structure and priorities before visual design begins. Reviewing wireframes early in a redesign is far cheaper than changing a page layout after it has been fully designed and built.; Related:Visual sitemap UX (user experience)UI (user interface)Staging site
WordPress: WordPress is a free, open-source content management system that a large share of websites are built on, ranging from simple blogs to business sites and online stores. The free software can be installed on almost any web hosting, and there is also a separate commercial hosted service built on the same software. Its huge range of themes and plugins makes it flexible, but sites built on it need regular core, theme and plugin updates to stay secure.; Related:CMS (content management system)Plugin Web hosting Front end and back end
XML sitemap: An XML sitemap is a file that lists the important pages of a website in a machine-readable format so search engines can discover and crawl them more efficiently. It can also include extra details, such as when a page was last updated. A sitemap does not guarantee that pages will be indexed, but submitting an updated one after a redesign helps search engines find the new URLs sooner.; Related:Visual sitemap robots.txt Search Console SEO (search engine optimization)