SEO glossary

301 redirect

A 301 redirect is a permanent redirect: it sends visitors and search engines from an old URL to a new one and tells Google to move the old page's ranking signals to the new address.

302 redirect

A 302 redirect is a temporary redirect. It sends visitors to another URL while telling search engines to keep the original URL in their index because the move won't last.

404 error

A 404 error is the HTTP status a server returns when a requested page doesn't exist. Search engines drop 404 pages from their index over time.

AI crawlers

AI crawlers are bots run by AI companies, such as GPTBot, OAI-SearchBot, ClaudeBot and PerplexityBot, that fetch web pages to train models or to answer users' questions with live search.

AI Mode

AI Mode is a chat-style search experience in Google Search, powered by Gemini, that answers complex questions in a conversation and links to sources, instead of showing a standard results page.

AI Overviews

AI Overviews are AI-generated summaries that Google shows at the top of some search results, answering the question directly and linking to the web pages it drew on.

AI visibility

AI visibility measures how often AI assistants like ChatGPT, Gemini, Perplexity, Claude and Google AI Overviews mention, recommend or cite your business when people ask them relevant questions.

Algorithm update

An algorithm update is a change Google makes to the systems that rank search results. Most are small and unannounced; some, like core updates and spam updates, are announced and can shift rankings widely.

Alt text

Alt text is a written description of an image, added in the HTML alt attribute. Screen readers read it aloud, browsers show it if the image fails to load, and search engines use it to understand the image.

Anchor text

Anchor text is the visible, clickable text of a link. Search engines use it as a clue to what the linked page is about.

Answer engine optimization (AEO)

Answer engine optimization (AEO) is shaping content so that search features and AI assistants can lift it as a direct answer, whether in a featured snippet, a voice reply or an AI-generated response.

Average position

Average position in Google Search Console is the mean of your site's topmost position in search results, averaged across every search where it appeared during the selected period.

Backlink

A backlink is a link from another website to yours. Search engines treat good backlinks as votes of confidence, so they remain one of the strongest signals for ranking.

Black hat SEO

Black hat SEO means tactics that try to trick search engines into ranking a site, breaking Google's spam policies. White hat SEO is the opposite: improving a site for users within the rules.

Breadcrumbs

Breadcrumbs are a row of links, usually near the top of a page, that show where the page sits in the site's structure, such as Home > Services > Water Heater Repair.

Broken link building

Broken link building is a link building method: find links on other sites that point to pages that no longer work, then suggest your own relevant page as a replacement.

Canonical tag

A canonical tag is a line of HTML that tells search engines which URL is the main version of a page when the same or very similar content is available at more than one address.

Click-through rate (CTR)

Click-through rate (CTR) is the percentage of people who saw your result and clicked it. In Google Search Console, it's clicks divided by impressions.

Clicks

In Google Search Console, a click is counted each time someone clicks a search result that takes them to your site. Clicks are the most direct measure of the traffic Google Search sends you.

Content brief

A content brief is a short planning document that tells a writer what a page should cover, who it's for, which search it targets and how it should be structured, before writing starts.

Content decay

Content decay is the gradual drop in organic traffic and rankings that a page experiences over time, usually because its information ages, competitors publish better pages or search intent shifts.

Content refresh

A content refresh is a meaningful update to an existing page (new facts, better answers, current examples, improved structure) to restore or improve its rankings and usefulness.

Conversion

A conversion is a valuable action a visitor takes on your site, such as a purchase, a booking, a form submission or a phone call. In Google Analytics 4 these are tracked as key events.

Core update

A core update is a broad, announced change to Google's main ranking systems, made several times a year. It changes how Google assesses content overall rather than targeting specific sites or issues.

Core Web Vitals

Core Web Vitals are three Google metrics that measure real visitors' experience of a page: loading (LCP), responsiveness (INP) and visual stability (CLS).

Crawl budget

Crawl budget is the number of URLs a search engine is able and willing to crawl on your site in a given period. It mostly matters for large sites with many thousands of pages.

Crawling

Crawling is how search engines discover pages: a bot such as Googlebot requests a URL, reads the page, and follows its links to find more URLs to visit.

Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) is the Core Web Vital that measures how much visible content unexpectedly moves around while a page is open. Good is a score of 0.1 or less.

Digital PR

Digital PR is earning coverage, mentions and links from online publications by giving journalists stories, data or expert comment they want to use.

Disavow

To disavow links is to ask Google, through a file uploaded in Search Console, to ignore specific backlinks or whole domains when assessing your site. Google says most sites never need to do this.

Domain authority

Domain authority is a broad term for how strong a website is in search, and also the name of Moz's 1 to 100 score (Ahrefs' version is Domain Rating). These scores are third-party estimates, not Google metrics.

Duplicate content

Duplicate content is the same or very similar content appearing at more than one URL, on your own site or across different sites. It splits ranking signals and makes Google choose which version to show.

E-E-A-T

E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness. It's the framework Google's quality raters use to judge whether content and its creators deserve to be trusted.

Ecommerce SEO

Ecommerce SEO is SEO for online stores: getting product and category pages found in search, handling large catalogs and filters, and turning search visitors into buyers.

Engagement rate and bounce rate

In Google Analytics 4, engagement rate is the share of sessions that lasted over 10 seconds, had a key event or viewed two or more pages. Bounce rate is the opposite: the share of sessions that were not engaged.

Faceted navigation

Faceted navigation is the set of filters on category pages (size, color, price, brand and so on) that let shoppers narrow a list. Each combination can create a new URL, which can cause crawling and duplicate content problems.

Featured snippet

A featured snippet is a highlighted answer Google shows near the top of some results pages, quoting a short passage, list or table from one web page along with a link to it.

Generative engine optimization (GEO)

Generative engine optimization (GEO) is the practice of making your business and content more likely to be mentioned, quoted and cited by AI tools such as ChatGPT, Gemini, Perplexity, Claude and Google's AI Overviews.

Google Analytics 4 (GA4)

Google Analytics 4 (GA4) is Google's free web analytics platform. It tracks visitors to your site, where they came from and what they did, using events instead of the older session-and-pageview model.

Google Business Profile

Google Business Profile (formerly Google My Business) is the free listing that controls how a business appears in Google Maps and the local results on Google Search.

Google sandbox

The Google sandbox is the informal name for the period when a new website struggles to rank, even with good content. Google says no sandbox exists, but new sites do take time to earn trust and visibility.

Google Search Console

Google Search Console is Google's free tool for site owners. It shows how your site performs in Google Search (clicks, impressions, queries, positions) and reports indexing, crawling and other technical problems.

Guest posting

Guest posting is writing an article for another website, usually with a byline and a link back to your own site. Done for real audiences it builds reputation; done at scale for links it breaks Google's rules.

H1 tag

The H1 tag is the main heading of a web page. It tells visitors and search engines what the page is about, and most pages should have exactly one.

Header tags

Header tags (H1 to H6) are the HTML headings that structure a page's content into sections and subsections, like chapters and sub-chapters in a book.

Helpful content

Helpful content is Google's term for people-first content: made to help readers, by people who know the subject, rather than made mainly to rank. Since March 2024 Google assesses it within its core ranking systems.

Hreflang

Hreflang is an HTML attribute that tells search engines which language and country each version of a page is for, so searchers see the version that fits them.

HSTS

HSTS (HTTP Strict Transport Security) is a response header that tells browsers to only ever connect to your site over HTTPS, even if someone types or clicks an http:// link.

HTTPS

HTTPS is the secure version of HTTP. It encrypts data between a visitor's browser and your website using a TLS certificate, and Google uses it as a light ranking signal.

Impressions

In Google Search Console, an impression is counted each time a link to your site appears in a user's search results, whether or not they scroll to it or click it.

Indexing

Indexing is when a search engine stores a crawled page in its database so it can be shown in search results. A page that isn't indexed can't rank for anything.

Interaction to Next Paint (INP)

Interaction to Next Paint (INP) is the Core Web Vital that measures how quickly a page visibly responds when someone clicks, taps or types. Good is 200 milliseconds or less.

Internal link

An internal link is a hyperlink from one page on your website to another page on the same website. Internal links help visitors move around and help search engines find and rank your pages.

JavaScript SEO

JavaScript SEO is the work of making sure search engines and AI crawlers can find, render and index content and links on sites that rely on JavaScript to build their pages.

JSON-LD

JSON-LD (JavaScript Object Notation for Linked Data) is the format Google recommends for adding structured data. It sits in a script tag, separate from the visible HTML.

Keyword

In SEO, a keyword is a word or phrase people type or say into a search engine. Businesses research keywords to learn what their customers search for and build pages that answer those searches.

Keyword cannibalization

Keyword cannibalization is when two or more pages on the same site compete for the same search, so Google keeps switching between them and neither ranks as well as one strong page would.

Keyword difficulty

Keyword difficulty is an estimate, usually on a 0 to 100 scale, of how hard it would be to rank on Google's first page for a keyword, based mainly on the strength of the pages that rank now.

Largest Contentful Paint (LCP)

Largest Contentful Paint (LCP) is a Core Web Vital that measures how long it takes for the biggest image or text block in the viewport to appear. Good is 2.5 seconds or less.

Lazy loading

Lazy loading delays downloading images, videos or iframes until they're about to scroll into view, so the first screen of a page loads faster and uses less data.

Link building

Link building is the work of getting other websites to link to yours, through outreach, useful content, partnerships, PR and listings, to improve rankings and referral traffic.

Link equity

Link equity (often called link juice) is the ranking value a link passes from one page to another. How much passes depends on the linking page's strength, relevance, placement and link attributes.

LLM citations

LLM citations are the links and source references that AI assistants such as ChatGPT, Perplexity, Gemini, Claude and Copilot attach to their answers, showing which web pages they drew on.

llms.txt

llms.txt is a proposed Markdown file placed at the root of a website that gives AI tools a short, clean summary of the site and links to its most useful pages. It's a community proposal, not an official standard.

Local citations

A local citation is any online mention of a business's name, address and phone number, such as a listing on Yelp, Apple Maps, Bing Places, a chamber of commerce site or an industry directory.

Local pack

The local pack (also called the map pack) is the box of usually three business listings with a map that Google shows for searches with local intent, such as 'plumber near me'.

Local rank grid

A local rank grid checks where a business ranks in Google's local results from many points spread across a map, then shows the positions as a colored grid, revealing how rankings change with location.

Local SEO

Local SEO is the work of helping a business appear when people nearby search for what it offers, in Google's map results, the local pack and location-based organic results.

Log file analysis

Log file analysis means reading your web server's access logs to see exactly which URLs search engine and AI crawlers requested, how often, and what response they got.

Long-tail keyword

A long-tail keyword is a specific, usually longer search phrase with lower search volume than a broad term, but clearer intent and often less competition.

Meta description

A meta description is a short summary of a page, set in its HTML, that search engines may show under the title in results. It doesn't affect rankings directly, but it can influence clicks.

Mixed content

Mixed content happens when a page loaded over HTTPS includes images, scripts, stylesheets or other files loaded over insecure HTTP. Browsers block or upgrade these requests and may show security warnings.

Mobile-first indexing

Mobile-first indexing means Google crawls and indexes the mobile version of your pages and uses it for ranking, even for people searching on desktop.

NAP

NAP stands for Name, Address and Phone number. In local SEO, keeping your NAP identical across your website, Google Business Profile and online directories helps search engines trust your business details.

Nofollow link

A nofollow link has rel="nofollow" in its HTML, asking search engines not to treat it as an endorsement. Since 2019 Google treats nofollow as a hint. Links without it are informally called dofollow links.

Noindex

Noindex is an instruction, set in a meta robots tag or an HTTP header, that tells search engines not to show a page in their results.

Off-page SEO

Off-page SEO covers everything outside your own website that influences rankings, mainly backlinks, but also brand mentions, reviews, citations and your reputation across the web.

On-page SEO

On-page SEO is optimizing the content and HTML of individual pages, including text, title tags, headings, images, internal links and URLs, so each page clearly answers a search and is easy for search engines to understand.

Online reviews

Online reviews are customers' public ratings and comments about a business on Google, Yelp, Facebook and similar sites. They influence local rankings and, even more, whether people choose you.

Organic traffic

Organic traffic is visits to your website from unpaid search results, as opposed to visits from ads, social media, email or links on other sites.

Orphan page

An orphan page is a page on your site that no other page links to. Visitors can't reach it by clicking, and search engines find it slowly or treat it as unimportant.

Pagination

Pagination splits a long list of items, such as blog posts or products, across a series of numbered pages (page 1, 2, 3 and so on) instead of showing everything on one page.

People Also Ask

People Also Ask (PAA) is a Google results box that shows related questions. Clicking a question expands a short answer taken from a web page, and often adds more questions below.

Pillar page

A pillar page is a broad, in-depth page on a core topic that links to more detailed pages on each subtopic. It sits at the center of a topic cluster.

Programmatic SEO

Programmatic SEO is creating many search-targeted pages from a template and a dataset, such as one page per city, product or integration, instead of writing each page by hand.

Proximity

In local SEO, proximity is the distance between a searcher (or the place they searched for) and a business. Google calls it distance, and it's one of its three main local ranking factors.

Rank tracking

Rank tracking is regularly checking where your pages appear in search results for a chosen list of keywords, from a set location and device, so you can see changes over time.

Redirect chain

A redirect chain is when one URL redirects to another URL that redirects again, so a visitor or crawler passes through two or more hops before reaching the final page.

Referring domain

A referring domain is a unique website that links to yours. Ten links from one site count as one referring domain; ten links from ten different sites count as ten.

Render-blocking resources

Render-blocking resources are CSS and JavaScript files that the browser must download and process before it can show anything on screen, which delays the first view of the page.

Robots.txt

Robots.txt is a plain text file at the root of a website that tells crawlers which paths they may or may not request. It controls crawling, not indexing.

Schema markup

Schema markup is code using the Schema.org vocabulary that describes the things on a page (a business, product, person, article or event) so search engines and AI tools can understand them.

Search intent

Search intent is the reason behind a search: what the person actually wants to find, do or buy. Pages that match the intent of a search are the ones that rank.

Search volume

Search volume is the estimated number of times a keyword is searched in a given place each month, usually shown as a monthly average over the past year.

SEO (search engine optimization)

SEO, or search engine optimization, is the work of improving a website and its presence online so it appears more often, and higher, in unpaid search results for the searches that matter to the business.

SEO audit

An SEO audit is a structured check of a website for problems that stop it ranking or converting: technical issues, on-page gaps, content quality, links, speed, mobile usability and, increasingly, AI readiness.

SEO KPI

An SEO KPI (key performance indicator) is a metric chosen to show whether SEO is meeting a business goal, such as leads from organic search, non-branded clicks or rankings for priority keywords.

SERP

SERP stands for search engine results page: the page a search engine shows after someone searches, including organic results, ads, maps, AI answers and other features.

SERP features

SERP features are any results on a search page other than the standard blue links, such as AI Overviews, featured snippets, the local pack, People Also Ask, images, videos and shopping results.

Service area business

A service area business (SAB) serves customers at their location, like a plumber, cleaner or mobile mechanic, rather than at a public storefront. On Google Business Profile, it can hide its address and list service areas instead.

Share of voice

In SEO, share of voice estimates what portion of the search visibility for a set of keywords goes to your site compared with competitors, usually weighted by search volume and ranking position.

Soft 404

A soft 404 is a page that tells visitors it doesn't exist, or has almost no content, but returns a 200 OK status code instead of a 404. Google flags these and usually won't index them.

Sponsored and UGC links

rel="sponsored" marks links that were paid for (ads, sponsorships, affiliate links), and rel="ugc" marks links in user-generated content like comments and forum posts. Google introduced both in 2019.

Structured data

Structured data is information added to a page in a standard, machine-readable format so search engines can understand exactly what the page describes, such as a business, product, event or article.

Technical SEO

Technical SEO is the part of SEO that makes sure search engines can crawl, render, index and understand a website, covering things like site structure, speed, redirects, robots rules, HTTPS and structured data.

Thin content

Thin content is a page that offers little or no real value to the reader: too short to answer the question, copied from elsewhere, or mass-produced with only small changes.

Time to First Byte (TTFB)

Time to First Byte (TTFB) is how long it takes from requesting a page until the first byte of the response arrives. It reflects server speed, redirects and network distance.

Title tag

The title tag is the HTML element that names a page. Google usually shows it as the clickable headline in search results, and it's one of the clearest signals of what a page is about.

Topic cluster

A topic cluster is a group of pages on one subject: a central pillar page covering the topic broadly, linked to several cluster pages that each cover one subtopic in depth.

Topical authority

Topical authority is the idea that a site which covers a subject thoroughly and well becomes more trusted by search engines for searches on that subject.

Toxic backlinks

Toxic backlinks is a term SEO tools use for links that look spammy or manipulative. Google ignores most such links automatically; they only become a real problem when they are part of a deliberate link scheme.

User agent

A user agent is the text a browser or bot sends with each request to identify itself, such as Googlebot, a Chrome browser on Android, or an AI crawler like GPTBot.

White-label reporting

White-label reporting means producing SEO reports under your own agency's brand (your logo, colors and name) rather than the brand of the software that generated them.

WordPress SEO plugin

A WordPress SEO plugin, such as Yoast SEO, Rank Math, SEOPress or All in One SEO, adds the SEO controls WordPress lacks: titles and descriptions, sitemaps, canonical tags, schema, redirects and more.

XML sitemap

An XML sitemap is a file that lists the URLs on your site you want search engines to find, often with the date each page last changed.

YMYL

YMYL stands for Your Money or Your Life: topics that could significantly affect a person's health, financial stability, safety or wellbeing. Google holds these pages to a higher standard of trust.

Zero-click search

A zero-click search is a search that ends without the person clicking through to any website, usually because the answer appeared on the results page itself.