SEO glossary: the terms, in plain English

SEO has a jargon problem. A proposal that says it will "fix canonicalisation, build topical authority and improve E-E-A-T" is making three claims a business owner cannot check without a translation. This page is that translation. Each term is defined in one or two sentences, with an example drawn from the kind of London business we work with, and where a definition rests on something Google has published, the source is linked.

Terms are grouped by topic rather than alphabetically, because the groups are how the work is organised: how search works, keywords, on-page, technical, links, local, content quality, AI search, measurement, ecommerce and the commercial words you meet in a contract. If you have a report in front of you, start with the measurement section. If you have a proposal, start with the commercial section at the end.

How search works

Search engine optimisation (SEO)

The work of making a website easier for search engines to find, understand and trust, so it appears for the searches its customers make. For a Croydon plumber, that means showing up for "emergency plumber Croydon" without paying for every click.

Crawling

The first stage of search: Google downloads pages with automated programs called crawlers (Googlebot), mostly by following links. Google describes the three stages as crawling, indexing and serving in its How Search Works documentation.

Indexing

The second stage: Google analyses a crawled page and stores what it learns in its index, a very large database. A page that is crawled but not indexed cannot rank, which is why "crawled, currently not indexed" in Search Console matters.

Ranking (serving)

The third stage: when someone searches, Google chooses and orders pages from its index. Google says one of the quality factors is "understanding if other prominent websites link or refer to the content", per its ranking results page.

Algorithm

The set of rules and models Google uses to rank. There is no single algorithm; Google publishes a guide to its ranking systems naming systems such as PageRank, BERT, passage ranking and spam detection.

Core update

A broad, announced change to Google’s ranking systems, usually several times a year. Traffic that moves on the date of a core update is not a penalty; it is a re-assessment. See the penalties and recovery guide.

SERP

Search engine results page: everything you see after searching. For "dentist Islington" the SERP has ads, a map with three practices, organic links, questions and sometimes an AI summary. Each of those is a different place to compete.

Organic results

The unpaid listings on a results page. SEO is the work of earning these; paid search (PPC) is the work of buying the ads above them. The SEO vs Google Ads guide compares the two.

Query

The words a person types or says. "Best brunch Clapham" and "brunch near me" are different queries that may want the same page, which is why pages are planned around intent rather than exact words.

Search intent

What the searcher is trying to do: learn something, compare options, buy, or get somewhere. "How much is Invisalign in London" is informational; "Invisalign Marylebone book" is transactional. One page should serve one intent.

Featured snippet

A box at the top of some results quoting an answer from a page. It is won by answering the question directly in the first lines under a matching heading, not by any markup.

Zero-click search

A search that ends without anyone clicking a result, because the answer appeared on the results page itself (a map, a phone number, an AI summary). For a local business, a zero-click search that produced a phone call is still a win.

Keywords and intent

Keyword

A word or phrase a page is intended to rank for. In practice a page targets a cluster of related phrases, not one word: "accountant Shoreditch", "Shoreditch accountants", "small business accountant EC2".

Head term

A short, high-volume, highly competitive phrase such as "solicitor London". Head terms are expensive to win and often vague about intent.

Long-tail keyword

A longer, more specific phrase with less volume and clearer intent: "fixed fee conveyancing solicitor Wandsworth". Most of a site’s useful traffic is many long-tail phrases added together.

Search volume

An estimate of how often a phrase is searched each month, usually from a third-party tool. Treat it as a rough order of magnitude, not a fact; tools disagree and local phrases are often under-counted.

Keyword difficulty

A tool’s score for how hard a phrase is to rank for, normally based on the links of the pages already ranking. Useful for comparing phrases against each other, meaningless as an absolute.

Keyword cannibalisation

Two or more of your pages competing for the same phrase, so Google alternates between them and neither ranks well. The fix is one page per intent, which is how this site is built: every search phrase here belongs to exactly one page.

Intent mapping

The planning step of listing the searches that matter, deciding what each searcher wants, and assigning each to one page type. The content guide walks through it.

Branded search

Searches that include your name ("Blac Whetstone menu"). Non-branded searches are the ones you are fighting for; branded searches are the ones you must never lose.

Seasonality

Predictable rises and falls in demand across the year. "Air conditioning installer London" peaks in June; "tax return accountant" peaks in January. Reports should compare year on year, not month on month.

Modifier

A word added to a core phrase that changes intent: "cheap", "best", "near me", "cost", "reviews", "emergency". Modifiers tell you which page type to build.

On-page

Title tag and title link

The title element in a page’s HTML, and the blue link Google shows for it. Google says it uses several sources to generate the title link and may rewrite yours, per its title link documentation. Keep titles unique, clear and about the page.

Meta description

A short summary in the page’s HTML. Google says it may use it for the snippet "when it describes the page better than other parts of the content", per its snippet documentation. It is not a ranking factor; it is an advert for the click.

Snippet

The description Google shows under a title link. It is often drawn from the page itself rather than the meta description, so the first lines of a page should say plainly what it is.

Headings (H1, H2, H3)

The structure of a page as marked in HTML. One H1 saying what the page is; H2s for sections; H3s inside them. Headings help readers skim and help Google understand which passage answers which question.

URL slug

The readable part of an address after the domain: /services/local-seo/. Short, lower-case, hyphenated and descriptive. Changing a slug is a redirect job, not a rename.

Alt text

A text description of an image for people using screen readers and for search engines. Google recommends descriptive filenames, titles and alt text in its image best practices. Describe the picture; do not stuff it with keywords.

Internal link

A link from one page of your site to another. Internal links tell Google which pages matter and what they are about. A service page nobody links to from the navigation is close to invisible.

Anchor text

The clickable words of a link. "Our Hackney studio" tells Google more than "click here". Across external links, natural anchor text varies; a hundred links all saying "best SEO agency London" looks manufactured.

Breadcrumbs

The trail at the top of a page (Guides > Technical > SEO glossary) showing where it sits in the site. Useful for people, and markable with structured data so Google can show the path in results.

Duplicate content

The same or very similar content at more than one URL: a product reachable through three category paths, or a printer-friendly version. It wastes crawling and splits signals; canonical tags and redirects consolidate it.

Thin content

A page with little that is useful or distinct: a 150-word "SEO in Barnet" page that is identical to the Brent one with the name swapped. Thin pages at scale are a spam policy problem, not just a quality one.

Keyword stuffing

Repeating phrases unnaturally to influence ranking. It is listed among Google’s spam policies and it reads badly to the customers who matter.

Above the fold

What is visible before scrolling. On a phone it is a small area, so the first screen should carry the page’s purpose and one next step.

Image SEO

Giving images descriptive names and alt text, compressing them, serving the right size for the screen and placing them near the text they relate to. For a restaurant, it is how a dish photo ends up in Google Images.

Technical

robots.txt

A file that "tells search engine crawlers which URLs the crawler can access on your site". Google is explicit that it "is not a mechanism for keeping a web page out of Google", per its robots.txt introduction. Use noindex for that.

noindex

A rule in a page’s HTML or HTTP header telling Google not to include it in results. Google notes the page must not be blocked by robots.txt or the crawler will never see the rule, per its noindex documentation.

Canonical URL

The one address you want Google to treat as the main version when several URLs show the same content. Google says canonicals are specified through redirects, rel="canonical" link elements or HTTP headers, and sitemap inclusion, per its canonicalisation documentation.

Redirect (301, 302)

An instruction that one URL has moved to another. A 301 is permanent and is the standard tool for a site move or a renamed page; a 302 is temporary. Missing redirects are the commonest reason a redesign loses traffic. See the redesign checklist.

404 and soft 404

A 404 is the correct response for a page that no longer exists. A soft 404 is a page that says "not found" but returns a 200 "success" code, which confuses crawlers and wastes crawl budget.

Status code

The three-digit response a server sends with every page: 200 (fine), 301 (moved), 404 (gone), 500 (server error). A crawl of your site lists every one; anything other than 200 on a page you care about needs an explanation.

XML sitemap

A file listing the URLs you want crawled and when they last changed. It helps discovery; it does not force indexing. Keep only canonical, indexable pages in it.

Crawl budget

How many pages Google will fetch from your site in a period. Small sites rarely hit a limit; large ecommerce sites with filters generating millions of URLs do. See faceted navigation.

Rendering and JavaScript SEO

Many sites build the page in the browser with JavaScript. Google can render JavaScript but does so in a separate step, and content that only appears after interaction may be missed. Google’s JavaScript SEO basics explain the process.

Core Web Vitals

Google’s three user-experience measures: Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift. web.dev states the thresholds: LCP within 2.5 seconds, INP of 200 milliseconds or less, CLS of 0.1 or less, each measured at the 75th percentile of page loads, per web.dev. See the Core Web Vitals guide.

LCP (Largest Contentful Paint)

How long until the biggest visible element (usually a hero image or headline) has loaded. Good is 2.5 seconds or under. Oversized hero images are the usual culprit.

INP (Interaction to Next Paint)

How quickly the page responds when someone taps or clicks. Good is 200 milliseconds or under. Heavy scripts, chat widgets and tag managers are the usual culprits.

CLS (Cumulative Layout Shift)

How much the page jumps around while loading. Good is 0.1 or under. Images without set dimensions, late-loading ads and cookie banners cause it.

PageSpeed Insights

Google’s free tool reporting lab measurements and, where enough visitors exist, real-user field data for a URL. Field data is what counts for Core Web Vitals.

Mobile-first indexing

Google indexes and ranks using the mobile version of a page. If your mobile site hides content that the desktop site shows, Google does not see it.

HTTPS

The encrypted version of the web protocol, shown by the padlock. It is a baseline, not a differentiator; a site without it is flagged "not secure" by browsers.

Structured data (schema markup)

Code that labels what a page is about in a standard vocabulary (schema.org). Google describes it as "a standardized format for providing information about a page" and recommends JSON-LD, per its structured data introduction. See the schema markup guide.

JSON-LD

The format Google recommends for structured data: a block of script in the page head rather than tags woven through the text. Easier to maintain and to test.

Rich result

A search listing with extras such as star ratings, prices, FAQs or breadcrumbs, enabled by structured data. Markup makes a page eligible; it does not guarantee display. Google notes FAQ rich results are now shown only for well-known, authoritative government and health websites, per its FAQPage documentation.

Hreflang

Markup telling Google which language and country each version of a page is for. Google’s localised versions documentation requires every version to link to every other, including itself. See the international SEO guide.

Pagination

Splitting a long list across numbered pages (/blog/page/2/). Each page should be crawlable and link to the next; "load more" buttons that only work with JavaScript can hide products from Google.

Faceted navigation

Filters on category pages (size, colour, price) that each create a new URL. Left unmanaged they generate huge numbers of near-duplicate pages. The ecommerce SEO guide covers the controls.

Log file analysis

Reading the server’s record of every request to see what Googlebot actually crawls, how often and with what response. The only direct evidence of crawling you have.

Staging site

A private copy of your site used for testing. It must be blocked from indexing (password or noindex), or Google may index the copy and treat your live site as the duplicate.

CDN

Content delivery network: servers around the world that hold copies of your files so pages load quickly wherever the visitor is. Matters more when you sell beyond the UK.

Links and authority

Backlink

A link from another website to yours. Google’s SEO starter guide notes that "the vast majority of the new pages Google finds every day are through links", per the starter guide. Links from relevant, respected sites are a signal of trust.

Link building

Any deliberate effort to earn links: publishing something worth citing, digital PR, local partnerships, supplier pages. The link building guide separates what works from what gets sites penalised.

Digital PR

Earning coverage and links from journalists and publishers with newsworthy stories, data or expert comment, rather than by paying for placement.

PageRank

Google’s original measure of a page’s importance from the links pointing to it. Google still lists "link analysis systems and PageRank" among its core ranking systems, per its ranking systems guide. The public PageRank score was retired long ago.

nofollow, sponsored and ugc

Attributes on a link that tell Google how to treat it: sponsored for paid placements, ugc for user-generated content such as comments, nofollow when neither fits and you do not want to vouch for the target. Google says such links "will generally not be followed", per its outbound links documentation.

Dofollow

Informal term for an ordinary link with none of the attributes above. Not a real HTML value, but you will see it in link reports and in the sales pitches of people selling links.

Domain Rating and Domain Authority

Third-party scores (Ahrefs and Moz respectively) estimating a site’s link strength on a scale to 100. Google does not use them. They are useful for comparing sites, and widely abused as the only number in a link report.

Link spam

Google’s spam policy term for links intended to manipulate ranking. Its examples include "buying or selling links for ranking purposes", excessive link exchanges and "using automated programs or services to create links to your site", per the spam policies.

Guest post

An article you write for another site, usually with a link back. Legitimate when the site is relevant and would publish you anyway; link spam when it is bought from a marketplace of sites that exist to sell placements.

Private blog network (PBN)

A set of websites owned or controlled by one party for the purpose of linking to clients. A classic link scheme and a common hidden ingredient of cheap link packages.

Manual action

A penalty applied by a human reviewer at Google, reported in Search Console. "Unnatural links to your site" is one; Google describes it as a detected pattern of "unnatural, artificial, deceptive, or manipulative links", per its manual actions report help.

Disavow

A file telling Google to ignore specified links to your site. Google calls it "an advanced feature" to be used "only with caution", and only when you have many spammy links and a manual action or a likely one, per its disavow documentation. Most sites never need it.

Toxic links

A tool-vendor term for links scored as risky. Google has no such category and says it generally ignores low-quality links without help. A report full of "toxic" links is usually a reason to sell you a clean-up, not a problem you have.

Citation

A mention of your business name, address and phone on another site (a directory, a chamber of commerce listing). Important for local search consistency whether or not it includes a link.

Local search

Local SEO

Ranking for searches with local intent, in the map results and the organic results beneath. For most London service businesses it is the SEO that pays first. See local SEO for London businesses.

Google Business Profile (GBP)

The free listing that powers your presence on Google Maps and the local pack: hours, photos, reviews, posts, services. Formerly Google My Business. The Business Profile guide covers setup and upkeep.

Local pack (map pack)

The map with three business listings shown for local searches. Being one of the three for "dentist Islington" matters more than ranking fourth organically beneath it.

NAP

Name, address, phone. These should be written identically on your site, your Business Profile and every directory. "Ltd" on one and "Limited" on another is the kind of mismatch that erodes confidence.

Service-area business

A business that serves customers at their locations rather than at a shop. Google’s Business Profile guidelines say these should have one profile for the central office with a designated service area. Most trades are service-area businesses.

Proximity

How close the searcher is to the business. It is the local ranking factor you cannot change, and the reason "near me" results differ between Hackney and Hammersmith for the same search. See near me searches in London.

Prominence

How well known a business is, judged from reviews, links, mentions and the quality of its web presence. The local factor you can most influence.

Review velocity

How steadily new reviews arrive. Fifty reviews in one week then nothing for a year reads differently from one a week. The reviews guide covers how to ask within the rules.

Google Posts

Short updates published to your Business Profile: offers, events, news. A sign of an active business; not a ranking lever in themselves.

Local landing page

A page on your site for one location or one area you serve, with content specific to it. The distinction between a useful one and a thin one is whether it says anything that could not be said about every other area.

Geo-grid rank tracking

Checking a local ranking from many points across a map rather than one, because local results change street by street. The honest way to report map visibility for a business in a dense borough.

Multi-location SEO

Managing search presence for several branches: one profile and one page per location, consistent data, and governance over who changes what. See the multi-location guide.

Content and quality

E-E-A-T

Experience, expertise, authoritativeness and trust: the qualities Google’s quality raters look for. Google says "trust is most important" and that E-E-A-T "isn’t a specific ranking factor" but describes what its systems try to reward, per its helpful content guidance.

YMYL

"Your money or your life": topics that affect health, finances or safety, where Google says it gives E-E-A-T more weight. A Harley Street clinic’s content is judged more strictly than a florist’s.

Helpful content

Google’s shorthand for content made "primarily to help people" rather than to attract search visits. The separate helpful content system was folded into Google’s core ranking systems in March 2024, per its ranking systems guide.

Who, how and why

Google’s three questions for assessing content: is it clear who wrote it, how it was produced (including whether automation was involved) and why it exists. The "why" is the one Google calls "perhaps the most important", per its helpful content guidance.

Topical authority

Being the site that covers a subject thoroughly and credibly, so Google trusts you on related searches. A Camden estate agent that has written well about letting, selling and every NW postcode it covers has it; one with a single "services" page does not.

Pillar page and topic cluster

A pillar is the main page on a subject; the cluster is the set of specific pages linked to and from it. This glossary is a pillar for the technical guides linked throughout it.

Content brief

The document a writer works from: the search intent, the audience, the questions to answer, the structure, the sources, the internal links and who will sign it off. The content guide includes a template.

Content refresh

Updating an existing page with new facts, better structure or corrected errors. Google warns that changing a date when "the content has not substantially changed" is a warning sign, per its helpful content guidance.

Evergreen content

Content whose usefulness does not expire: how to choose an accountant, how to read a tenancy agreement. The opposite is news. Evergreen pages earn links for years if they are kept accurate.

Byline and author page

The name and credentials on an article and the page about that person. Google says to avoid "AI-generated headshots, made-up names, or false credentials", per its helpful content guidance. Real people only.

Quality rater guidelines

The published handbook Google’s human evaluators use to assess search results. Google says their ratings do not directly influence ranking; they are used to evaluate changes, per its AI content guidance.

Scaled content abuse

Google’s spam policy for producing "many pages for the primary purpose of manipulating search rankings and not helping users", whether by AI, scraping or automated translation, per the spam policies. The method does not matter; the volume without value does.

Programmatic SEO

Generating pages from data and templates: one page per borough, per product, per postcode. Fine when every page carries real, distinct information; scaled content abuse when it does not.

AI-generated content

Text produced with a generative model. Google says the question is quality, not method, and advises creators to fact-check output and consider disclosing how content was made, per its guidance on AI-generated content.

AI search

AI Overviews

The AI-written summary Google shows above some results, with links to the sources it drew on. Google says there are "no additional requirements to appear in AI Overviews or AI Mode", per its AI features documentation. See the AI Overviews guide.

AI Mode

Google’s conversational search experience, where the whole results page is an AI answer with cited sources. The same fundamentals apply: crawlable, clear, trustworthy content.

GEO (generative engine optimisation)

Making your content the kind that AI answers cite: direct statements, named sources, clear entities, consistent facts across the web. The AI search and GEO guide explains what is different and what is not.

AEO (answer engine optimisation)

An older label for a similar idea: structuring content so it can be lifted as a direct answer. In practice GEO and AEO describe the same work.

LLM (large language model)

The type of model behind ChatGPT, Gemini and Claude. It generates text from patterns; when it searches, it reads pages much as a crawler does, which is why technical accessibility still matters.

Citation (in AI answers)

A link an AI answer attaches to a statement. Being cited is the AI-search equivalent of ranking. Pages that state facts plainly and name their sources are cited more readily than pages that bury the answer.

Entity

A thing Google can identify unambiguously: a business, a person, a place. Consistent naming, a Business Profile, structured data and mentions on other sites make your business an entity rather than a string of words.

Knowledge panel

The box about an entity shown to the right of results (or at the top on a phone). For a business it is usually fed by the Business Profile.

llms.txt

A proposed plain-text file summarising a site for AI systems. Cheap to add and harmless; there is no evidence it changes visibility, so treat it as housekeeping rather than strategy.

Measurement and reporting

Google Search Console

Google’s free reporting tool for site owners: which queries show your pages, clicks, indexing problems, manual actions, links. The one data source in SEO that comes from Google itself. Insist on access in your own name.

Impressions

How many times a page of yours appeared in results, per Search Console’s performance report. Rising impressions before rising clicks is the normal shape of early progress.

Clicks

How many times someone clicked through from Google to your site. The number that should eventually turn into enquiries.

CTR (click-through rate)

Clicks divided by impressions. A low CTR at a good position usually means the title and snippet are not persuasive, or the result is competing with ads and a map.

Average position

The mean ranking of your topmost result for a query, as Search Console reports it. An average, so a page at position 1 for some searchers and 20 for others reports as 10.

Rank tracking

Checking positions for a chosen list of phrases from a chosen location each day or week with a third-party tool. Useful as a trend, misleading as a scorecard, because positions vary by location, device and person.

Share of voice (visibility)

A tool’s estimate of how much of the available search traffic for a set of phrases your site captures, weighted by position. Good for tracking a market; the method varies by tool.

GA4 (Google Analytics 4)

Google’s analytics platform, recording what visitors do on your site. It tells you what happened after the click: pages viewed, forms sent, calls tapped.

Conversion (key event)

A visitor doing the thing you wanted: a form sent, a call made, a booking, a sale. GA4 calls these key events. SEO reports that stop at traffic are stopping one step short.

Attribution

Deciding which channel gets credit when someone saw an ad, searched your name and then came back a week later from an organic result. No model is right; agree one and keep it.

UTM parameters

Tags added to links (utm_source, utm_medium) so analytics can tell where a visit came from. Never add them to internal links; they break the data.

Engagement rate

GA4's share of sessions that lasted over ten seconds, had a conversion or viewed two or more pages. It replaced bounce rate as the default measure of whether a visit was worth anything.

Baseline

The measurements taken before work starts, so that progress can be judged. Any agency that cannot show you the baseline cannot honestly show you progress. See what a good report includes.

Ecommerce

Category page (collection page)

A page listing products of one type. Category pages win the commercial searches ("linen shirts", "mid-century sideboards") because they match the breadth of what the searcher wants. Shopify calls them collections.

Product page

The page for one item. It wins specific searches and brand-plus-product searches, and needs unique descriptions, real photographs, price, stock and reviews marked up.

Product structured data

Markup giving price, availability, rating and identifiers for a product, so Google can show them in results and in Shopping.

Merchant Center and product feed

Google’s system for receiving your product data, used for Shopping ads and for free product listings. A clean feed is as much SEO as it is advertising.

Out-of-stock handling

What happens to a product URL when the item sells out: keep it live with a "notify me" if it returns, redirect to the category if it does not. Deleting pages that have links and rankings throws value away.

Headless commerce

A set-up where the storefront is built separately from the commerce platform, usually with JavaScript. Fast when done well; a rendering problem for search when done badly.

Commercial and contract terms

SEO audit

A structured review of a site’s technical health, content and authority, with prioritised fixes. A real one is written by a person who looked at your site; an automated "score" is not an audit. Our free review is the former.

Retainer

A fixed monthly fee for an agreed scope of ongoing work. Ask what is delivered in month one and what happens if it is not. See our pricing and the cost guide.

Minimum term

The shortest period a contract binds you for. Six and twelve months are common in the market. What matters is that it is stated plainly before you sign, with the notice period and exit cost. See contracts and guarantees.

Deliverables

The concrete outputs promised: pages written, fixes shipped, links earned, reports sent. An agency that promises rankings and not deliverables is promising something it does not control.

Guarantee

In SEO, a promise of a ranking or traffic result. Nobody controls Google’s results, so no honest agency gives one; the honest version guarantees the work, not the outcome. Our code of ethics says so in writing.

White hat and black hat

Old slang for work within Google’s policies and work that breaks them. The useful question is more specific: does the proposal involve anything in Google’s spam policies?

White-label SEO

SEO delivered by one agency and sold under another’s name. Common and legitimate; you should still know who does the work. See white-label SEO.

Site migration

Moving a website to a new domain, platform or URL structure. The single riskiest event in a site’s SEO life, and the one most often done without a plan. See the migration checklist.

Penalty

Loosely, any Google-caused drop. Strictly, a manual action. Most drops are algorithmic re-assessments, not penalties, and the recovery is different for each.

Negative SEO

An attempt to harm a competitor with spammy links or scraped content. Rare in practice, and Google says it generally ignores such links; it is a far more common excuse than cause.

Sandbox

The belief that new sites are held back for a period. Google has never confirmed one; new sites simply have no history, few links and little content, which looks the same from the outside.

Churn and burn

A tactic of ranking a disposable site with spam, profiting briefly and abandoning it when penalised. Irrelevant to a real business with a name to protect, and a reason to be wary of agencies that treat your domain as disposable.

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