SEO glossary

54 SEO terms in plain English. Each entry gives a short definition, a fuller explanation, and what the term means for you when you're hiring or managing an SEO agency.

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301 redirect: A 301 redirect permanently sends visitors and search engines from one URL to another. It's the standard way to move a page, merge duplicate pages or change a site's domain. Google treats a permanent redirect as a strong signal that the new URL should be shown in search results instead of the old one. Read more

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AI Overviews: AI Overviews are AI-generated summaries that Google shows at the top of some search results, with links to the web pages they draw on. Google says pages need no special optimisation to appear: they must be indexed and eligible to show a snippet, and standard SEO best practice applies. Read more
Alt text: Alt text is a short written description of an image, added in the image's alt attribute in HTML. Screen readers read it aloud to people who can't see the image, and search engines use it, along with surrounding text, to understand what an image shows and how it relates to the page. Read more
Anchor text: Anchor text is the clickable text of a link. It tells users and search engines what to expect on the page being linked to. Descriptive anchor text, such as 'commercial cleaning prices', helps more than vague text like 'click here', on both internal links and links from other websites. Read more
Answer engine optimisation (AEO): Answer engine optimisation (AEO) is the practice of structuring content so that search features, voice assistants and AI tools can pull a direct answer from it. In practice it overlaps heavily with standard SEO: clear questions and answers, accurate facts, and pages that search engines can crawl and understand. Read more

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Backlink: A backlink is a link from another website to yours. Search engines treat links as one sign that a page is useful or trusted, and they use links to discover new pages. A few relevant links from respected sites are worth far more than many links from low-quality or unrelated ones. Read more
Black-hat SEO: Black-hat SEO is the use of tactics that try to manipulate search rankings in ways that break search engine rules, such as buying links, hiding text, cloaking or mass-producing low-value pages. It can bring short-term gains, but it risks lower rankings or removal from Google's results. Read more
Breadcrumbs: Breadcrumbs are a row of links, usually near the top of a page, that show where the page sits in a website's structure, such as Home › Services › Local SEO. They help visitors move around and help search engines understand site hierarchy. Google may show them in search results. Read more

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Canonical tag: A canonical tag is a line of HTML, rel="canonical", that tells search engines which URL is the preferred version of a page when the same or very similar content is available at several addresses. It helps consolidate signals onto one URL, but Google treats it as a strong hint, not a command. Read more
Click-through rate (CTR): Click-through rate (CTR) is the percentage of people who click on a result after seeing it. In SEO it usually means organic CTR: clicks divided by impressions in search results, as reported in Google Search Console. It depends on position, the title and snippet, and what else appears on the page. Read more
Conversion rate: Conversion rate is the percentage of visitors who complete a goal you care about, such as making an enquiry, booking, signing up or buying. In SEO it shows whether organic traffic turns into business. It is calculated as conversions divided by sessions or users, then multiplied by 100. Read more
Core update: A core update is a broad change Google makes to its main ranking systems, typically several times a year. Core updates aren't aimed at specific sites or penalties. They change how content is assessed overall, so some pages rise and others fall. Google announces them and says a drop doesn't necessarily mean something is wrong. Read more
Core Web Vitals: Core Web Vitals are three Google metrics for real-world page experience: Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness) and Cumulative Layout Shift (visual stability). Google uses them in its page experience assessment, measured from real Chrome users and reported in Search Console. Read more
Crawl budget: Crawl budget is the number of URLs a search engine can and wants to crawl on your site in a given period. It is mainly a concern for very large or frequently updated sites. Wasting it on duplicate, filtered or broken URLs can delay the discovery of the pages that matter. Read more
Crawling: Crawling is the process search engines use to discover and download web pages. Automated programs called crawlers or bots, such as Googlebot, follow links and read sitemaps to find URLs, then fetch them. A page that can't be crawled can't usually be indexed or shown in search results. Read more

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Domain Authority: Domain Authority is a score from the SEO tool provider Moz, on a scale of 1 to 100, that predicts how likely a whole website is to rank compared with others, based mainly on its links. Similar scores include Ahrefs' Domain Rating. These are third-party estimates, not metrics Google uses. Read more
Duplicate content: Duplicate content is the same or very similar content appearing at more than one URL, on one site or across several. It usually happens by accident, through URL parameters, print pages or product variants. Google says it isn't a penalty in itself, but it splits signals and makes Google choose which version to show. Read more

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E-E-A-T: E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness. It comes from Google's Search Quality Rater Guidelines, which human reviewers use to assess result quality. It isn't a single ranking factor, but it describes the qualities Google's systems aim to reward, with trust the most important. Read more

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Featured snippet: A featured snippet is a highlighted excerpt from a web page that Google sometimes shows near the top of results to answer a question directly, with a link to the source. Google selects snippets automatically from pages it has indexed. There's no markup that guarantees one, but clear, direct answers help. Read more

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Generative engine optimisation (GEO): Generative engine optimisation (GEO) means improving the chance that AI systems such as Google's AI Overviews, ChatGPT or Perplexity cite or mention your brand and pages in their generated answers. It builds on SEO fundamentals: accessible, accurate, well-sourced content and a reputation that other credible sites reference. Read more
Google Analytics 4 (GA4): Google Analytics 4 (GA4) is Google's free web and app analytics tool. It records visits, engagement and actions such as enquiries or purchases, and shows which channels they came from, including organic search. GA4 replaced Universal Analytics, which Google stopped processing data for in July 2023. Read more
Google Business Profile: Google Business Profile is Google's free listing for businesses with a physical location or service area. It controls how a business appears in Google Maps and the local pack: name, address, hours, categories, photos and reviews. Google says local ranking depends mainly on relevance, distance and prominence. Read more
Google Search Console: Google Search Console is Google's free tool for site owners. It shows how your site performs in Google Search (impressions, clicks, average position and queries), which pages are indexed and why others aren't, and alerts you to problems such as manual actions, security issues and Core Web Vitals failures. Read more

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Helpful content: Helpful content is Google's term for content created primarily to help people rather than to rank in search engines. Google's guidance asks whether content shows first-hand expertise, satisfies the reader and offers original value. Its ranking systems aim to reward such content and demote unhelpful, search-first pages. Read more
Hreflang: Hreflang is an HTML attribute that tells search engines which language or regional version of a page to show to which users, for example English for Australia versus English for the United Kingdom. It helps the right version appear in each market and is used on multilingual and multi-country websites. Read more

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Indexing: Indexing is the stage where a search engine processes a crawled page, works out what it is about and stores it in its index, the database it draws results from. Only indexed pages can appear in search results. Google doesn't index every page it crawls, and indexing is never guaranteed. Read more
Internal linking: Internal linking means linking from one page on your website to another. Internal links help visitors find related content, help search engines discover pages and understand how they relate, and pass authority from strong pages to others. Descriptive anchor text and a clear site structure make them more effective. Read more

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JavaScript SEO: JavaScript SEO is the work of making sure search engines can crawl, render and index websites that rely on JavaScript to display content or links. Google can run JavaScript, but rendering may be delayed and some patterns break it. Content and links that exist only after scripts run carry extra risk. Read more

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Keyword cannibalisation: Keyword cannibalisation happens when several pages on the same website target the same search and compete with each other. Search engines may switch between them or rank neither well. It's usually fixed by merging pages, redirecting duplicates, or giving each page a distinct purpose and clearer internal links. Read more
Keyword difficulty: Keyword difficulty is a score that SEO tools use to estimate how hard it would be to rank on page one for a search term, usually based on the strength of pages that already rank. Each tool calculates it differently. It's a rough guide for prioritising, not a measure Google publishes. Read more
Keyword research: Keyword research is the process of finding the words and phrases people type into search engines when looking for what you offer, then judging each by relevance, intent, volume and competition. It shapes which pages a site needs, what they should cover and which searches to prioritise. Read more

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Link building: Link building is the work of earning links to your website from other sites. Links help search engines discover pages and are one of the signals of how others regard them. Ethical link building earns links through useful content, research, PR and genuine relationships; buying links that pass ranking credit breaks Google's rules. Read more
Local pack: The local pack is the block of map results Google shows for searches with local intent, such as 'dentist near me' or 'plumber Leeds'. It usually lists a few businesses from Google Maps with ratings, address and opening hours. Rankings come from Google Business Profile data, based on relevance, distance and prominence. Read more
Local SEO: Local SEO is the work of making a business more visible in searches with local intent, such as 'accountant near me' or 'florist in Bristol'. It covers the Google Business Profile, local pack and maps results, location and service pages, reviews and consistent business details across the web. Read more
Long-tail keywords: Long-tail keywords are specific, usually longer search phrases that each have low search volume, such as 'waterproof hiking boots for wide feet' rather than 'hiking boots'. Together they make up a large share of searches. They're often less competitive and closer to a purchase, so they can convert well. Read more

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Manual action: A manual action is a penalty applied by a human reviewer at Google when a site breaks Google's spam policies. It can lower rankings for some pages or remove the whole site from results. Manual actions are reported in Google Search Console, and site owners can request a review once the problem is fixed. Read more
Meta description: A meta description is an HTML tag that summarises a page's content. Search engines may use it as the snippet beneath the title in search results, but Google often writes its own snippet from page text instead. It isn't a ranking factor, but a clear, accurate description can encourage clicks. Read more
Mobile-first indexing: Mobile-first indexing means Google predominantly uses the mobile version of a page's content for indexing and ranking. If the mobile version is missing content, links, images or structured data that appear on desktop, Google may not see them. Google completed the switch to mobile-first indexing for nearly all sites. Read more

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Nofollow, sponsored and ugc: Nofollow, sponsored and ugc are values of a link's rel attribute that tell search engines about the relationship behind a link. Sponsored marks paid or affiliate links, ugc marks user-generated links such as comments, and nofollow is a general hint not to associate your site with the target. Google treats them as hints. Read more
Noindex: Noindex is a directive that tells search engines not to include a page in their results. It's set with a robots meta tag in the page's HTML or an X-Robots-Tag HTTP header. The page must remain crawlable for search engines to see the directive; blocking it in robots.txt can stop noindex working. Read more

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Off-page SEO: Off-page SEO covers activity outside your own website that affects how search engines and people regard it: mainly earning links from other sites, but also brand mentions, reviews, digital PR and local citations. It complements on-page and technical SEO, which deal with your own pages. Read more
On-page SEO: On-page SEO is the work done on individual pages to help them rank and serve visitors: matching content to search intent, writing clear titles and headings, structuring information, adding internal links, describing images and using structured data where it fits. It's the part of SEO most directly under your control. Read more
Organic traffic: Organic traffic is visits to your website from unpaid search results, as opposed to paid ads, social media, email or direct visits. It's the main volume measure for SEO. In Google Analytics it appears as the Organic Search channel; Google Search Console reports the clicks behind it. Read more

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Page Authority: Page Authority is a score estimating how strong an individual page is likely to be in search results, based mainly on the links pointing to it. Moz's Page Authority is the best-known version, on a 1 to 100 scale. Like other third-party authority scores, it's an estimate, not a Google metric. Read more

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Robots.txt: Robots.txt is a plain-text file at the root of a website that tells search engine crawlers which parts of the site they may or may not crawl. It manages crawling, not indexing: a page blocked in robots.txt can still appear in results if other pages link to it, usually without a description. Read more

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Schema markup: Schema markup, or structured data, is code added to a page that describes its content in a standard vocabulary from schema.org, such as a product's price or an article's author. Search engines use it to understand pages and may show rich results, such as review stars or breadcrumbs, for supported types. Read more
Search engine results page (SERP): A search engine results page (SERP) is the page a search engine shows in response to a query. Beyond the familiar list of links, it may include ads, a local map pack, AI Overviews, featured snippets, images, videos, product listings and People also ask questions. Its layout varies by query, location and device. Read more
Search intent: Search intent is the goal behind a search: what the person actually wants to find or do. Common types are informational (learn something), commercial (compare options), transactional (buy or book) and navigational (find a specific site). Pages that match the intent behind a search are far more likely to rank and convert. Read more
SEO audit: An SEO audit is a structured review of a website's search performance and problems, usually covering technical health, content and relevance, and links and authority. A useful audit ends with a prioritised list of fixes, with the expected impact and effort for each, rather than a raw export from a crawling tool. Read more
Site migration: A site migration is any major change to a website that can affect search visibility, such as moving to a new domain, switching to HTTPS, changing platform or CMS, restructuring URLs or merging sites. Without careful planning, especially redirects, migrations can cause large and lasting drops in organic traffic. Read more

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Technical SEO: Technical SEO is the work of making sure search engines can crawl, render, index and understand a website. It covers site structure, robots.txt and sitemaps, redirects and canonical tags, page speed and Core Web Vitals, mobile parity, JavaScript rendering, structured data, international setup and security. Read more
Title tag: A title tag is the HTML element that gives a page its title, shown in browser tabs and used by Google as the main source for the clickable headline in search results, called the title link. A clear, specific and accurate title helps search engines understand the page and encourages people to click. Read more
Topical authority: Topical authority describes how strongly a website is associated with a subject, built by covering it in depth, accurately and from genuine expertise, with related pages linked together. It's an industry concept rather than a Google metric, but it reflects how search engines judge which sources to trust on a topic. Read more

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XML sitemap: An XML sitemap is a file that lists the URLs on a website you want search engines to crawl, often with the date each page was last changed. It helps search engines find pages, especially on large, new or poorly linked sites. Listing a URL doesn't guarantee it will be crawled or indexed. Read more

Hiring guideQuestions to Ask an SEO Agency Before HiringWhat to ask in a pitch meeting, what good and bad answers sound like, and a printable checklist to score each agency.9 min read Hiring guideWhat to Expect in the First 3 Months of SEOMonth by month: what a good agency does in the first 90 days, what you should receive, and what results are realistic.8 min read Hiring guideHow to Spot Fake SEO GuaranteesWhy ranking guarantees can't be real, the wordings to watch for, what Google says, and what an honest commitment looks like.8 min read

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