SEO glossary
117 SEO terms explained in plain English, each with an example from a real-world kind of business, a quick way to check your own site and the mistakes to avoid.
SEO is full of jargon, and some of it gets used to make simple work sound complicated. Each entry here explains what a term means, why it matters to a small business and how to check it yourself, usually with free tools such as Google Search Console.
Where a term relates to Google's own rules or features, we link to Google's documentation so you can read the source for yourself.
SEO (Search Engine Optimisation)
The practice of improving a website so it can be found in unpaid search results for relevant queries.
SERP
Search engine results page: the page of results a search engine shows for a query.
Keyword
A word or phrase people type into search engines, used to plan pages and measure visibility.
Long-tail keyword
A longer, more specific search phrase, often closer to a decision and sometimes easier to rank for.
Search intent
The likely goal behind a query: learn, navigate, compare or buy.
On-page SEO
Optimising titles, headings, content, internal links and HTML on your own pages.
Off-page SEO
Signals outside your site that affect rankings, especially links and brand mentions.
Technical SEO
Making a site crawlable, indexable, fast and structured so search engines can understand it.
Crawl
When a search engine bot discovers URLs by following links and sitemaps.
Index
The searchable database of pages a search engine may show in results.
Googlebot
Google's main web crawler that fetches pages for indexing.
robots.txt
A file that suggests which parts of a site crawlers may fetch.
XML sitemap
A file listing important URLs to help search engines discover pages.
Canonical URL
The preferred URL for duplicate or similar content, declared with rel=canonical.
Meta description
An HTML summary of a page that Google may show under the title in results. It isn't a direct ranking factor.
Title tag
The HTML title of a page. It matters for relevance and for whether people click.
H1
The main visible heading on a page; should describe the topic clearly.
Internal linking
Links between pages on the same site that help users and distribute crawl paths.
Backlink
A link from another website to yours; a classic off-page signal.
Anchor text
The clickable text of a link, giving context about the destination.
Domain authority
A third-party score that estimates a site's ranking strength. It isn't a Google metric.
Domain Rating
Ahrefs' third-party score for a site's backlink profile strength.
nofollow
A link attribute hinting the link should not pass ranking credit in the usual way.
E-E-A-T
Experience, expertise, authoritativeness and trust: quality concepts from Google's rater guidelines.
Helpful content
Content created for people first, aligned with Google's helpful content guidance.
Core Web Vitals
Google user-experience metrics: LCP, INP and CLS.
LCP
Largest Contentful Paint: how quickly the main content of a page loads.
INP
Interaction to Next Paint: how quickly a page responds when people interact with it.
CLS
Cumulative Layout Shift: how much a page's layout jumps around while it loads.
Schema (structured data)
Standardised markup that clarifies entities for search engines.
JSON-LD
A common format for embedding schema.org structured data.
FAQ schema
FAQPage structured data for question-and-answer content. Google stopped showing FAQ rich results in 2026.
Breadcrumb schema
Structured data describing the page's position in the site hierarchy.
Local SEO
Optimising to appear in local pack and localised organic results.
Google Business Profile
Google's free business listing used in Maps and local pack results.
NAP
Name, address and phone number. Keeping them consistent supports local trust.
Citation
A mention of your business NAP on another site or directory.
Local pack
The map-based local results block on many Google SERPs.
hreflang
Annotations that indicate language and regional URL variants.
Redirect
Sending users and crawlers from one URL to another.
301 redirect
A permanent redirect, commonly used in migrations.
404
Page not found response that should be fixed or thoughtfully redirected.
Soft 404
A URL that returns 200 but looks empty or erroneous to Google.
Orphan page
A page with no internal links pointing to it.
Crawl budget
Roughly how much attention Googlebot gives to crawling a site.
Thin content
Pages with little original value, a common problem with mass-produced pages.
Doorway page
Pages built mainly to rank for similar queries and funnel users elsewhere.
Duplicate content
Same or near-identical content on multiple URLs.
Keyword cannibalisation
Several pages competing for the same query and weakening each other.
Search volume
An estimate of how often a query is searched. Treat tool figures as rough estimates.
CTR
Click-through rate: clicks divided by impressions.
Impressions
How often a page appeared in search results.
Organic traffic
Visits from unpaid search results.
Ranking
A page's position for a query. It moves around more than most people expect.
Featured snippet
A highlighted answer box Google sometimes shows.
People Also Ask
Expandable related questions on many results pages.
AI Overview
Google's AI-generated summary unit on some queries.
GEO / AEO
Informal terms for visibility in generative or AI answer experiences.
Spam update
A Google announcement improving spam-detection systems.
Core update
A broad Google ranking update affecting many queries.
Manual action
A human-reviewed penalty visible in Search Console.
Disavow
A Search Console tool to ask Google to ignore specific backlinks.
Link building
Earning or acquiring backlinks: quality and relevance matter.
Digital PR
PR campaigns designed to earn coverage and links from real publications.
PBN
Private Blog Network: a manipulative link scheme Google targets.
Content cluster
A group of related pages linking to a pillar topic page.
Pillar page
A comprehensive hub page that clusters link to.
Topical authority
Perceived depth and coherence of content on a subject.
Content brief
Instructions covering intent, outline, links and unique angles.
Evergreen content
Content that stays useful over time and is worth updating.
Content decay
Traffic decline as pages age or competitors outpace them.
Mobile-first indexing
Google predominantly uses the mobile version of content for indexing.
HTTPS
Encrypted HTTP: expected for modern sites.
CDN
Content delivery network serving assets from edge locations.
Alt text
A text alternative for an image, written for people who can't see it.
Ecommerce SEO
SEO for product and category architectures and product content.
Faceted navigation
Filter URLs that can create crawl and duplicate issues if uncontrolled.
Google Search Console
Google's free property for coverage, queries and enhancements.
GA4
Google Analytics 4, Google's tool for measuring traffic and conversions.
Conversion rate
Share of visits that complete a goal such as an enquiry.
Branded search
Queries that include your brand name.
Zero-click search
When the SERP answers without a click to a website.
SERP feature
Non-classic result units such as maps, videos or AI Overviews.
White-hat SEO
Informal term for practices aligned with search guidelines.
Black-hat SEO
Manipulative tactics that violate spam policies.
Site migration
Moving URLs, hosts or platforms while preserving search equity.
URL slug
The path segment that names a page, ideally clear and stable.
Breadcrumb
Navigational trail showing where a page sits in the site.
Site architecture
How pages are organised and linked.
Log file analysis
Studying server logs to see how bots crawl your site.
IndexNow
Protocol to notify participating engines of URL changes (not Google).
Sitelinks
Additional links Google may show under a navigational result.
Knowledge panel
Entity information panel for some brands and topics.
Yandex
A major search engine in some markets; less central for UK SEO.
Bing
Microsoft's search engine; still worth basic optimisation.
Sponsored link
A rel value marking paid or sponsored links.
UGC link
Rel=ugc marks user-generated content links.
Canonicalisation
Choosing and declaring the preferred URL among duplicates.
Geo-targeting
Aligning pages and signals to a geographic market.
Keyword difficulty
Third-party estimates of how hard it is to rank for a term.
Guest post
Content on another site; useful when editorial, risky when spammy.
Google sandbox myth
Informal idea that new sites take time to rank: not an official feature.
AMP
Optional mobile framework; not required for good mobile SEO.
Lazy loading
Deferring offscreen images: careful with LCP images.
Image SEO
Filenames, alt text, compression and placement for images.
Video SEO
Optimising video pages and platforms for discovery.
Pagination
Splitting lists across pages with a clear crawl strategy.
Engagement metrics
Measures of how people engage with a page. In GA4, bounce rate is the opposite of engagement rate.
Grey-hat SEO
Informal label for risky tactics between clear-good and clear-spam.
SEO penalty
Ranking loss from algorithmic or manual spam enforcement.
SEO recovery
Work to regain visibility after a penalty or update impact.
Footer links
Sitewide footer links: useful for users, easy to overdo.
Header navigation
Primary menu links that shape crawl paths and UX.
llms.txt
A proposed file for AI tools. Google Search ignores it, so it doesn't affect rankings.
Anchor text mix
The mix of branded, naked and keyword anchors in a link profile.
Content refresh
Updating a page to restore accuracy and competitiveness.
UX and SEO
Overlap where usability, speed and clarity support search performance.
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