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30 researched definitions
SEO terminology, explained for real decisions.
A practical glossary for Google, Bing and AI search. Every term includes a direct definition, applied example, misconceptions, implementation steps, measurement, primary references and the relevant TheProjectSEO service.
Browse all definitionsA–Z index
Editorial standard
More than a one-sentence dictionary.
Short definitions are easy to generate. Useful definitions explain where the term applies, what it does not mean, how a practitioner implements it and which evidence would show that the work succeeded.
Start with Core Web Vitals in SEO, hreflang meaning, the People Also Ask definition, or the broader search engine optimization meaning.
Live SERP research
Each term has its own stored DataForSEO corpus and optimizer scorecard.
Primary references
Changing platform behavior is checked against official documentation.
Connected concepts
Related definitions, guides and services explain the term’s place in the system.
Practitioner boundaries
Tool metrics and emerging acronyms are not misrepresented as Google standards.
01
SEO fundamentals and links
14 definitions
SEO
SEO, or search engine optimization, is the work of improving a website so relevant people can discover, select and use its pages in unpaid search results.
Definition and useSERP
SERP means search engine results page: the page of organic results, ads and search features returned for a query.
Definition and useKeyword
An SEO keyword is a word or phrase used to represent a search need and connect that need to an intended page.
Definition and useLong-tail Keyword
A long-tail keyword is a relatively specific, lower-frequency search query, often expressing a narrow problem, attribute or decision.
Definition and useSearch Intent
Search intent is the task or outcome a person is trying to achieve with a query.
Definition and useKeyword Difficulty
Keyword difficulty is a third-party tool score estimating how competitive it may be to rank for a query, usually on a 0–100 scale.
Definition and useBacklink
A backlink is a link from a page on another website to a page on your website.
Definition and useReferring Domain
A referring domain is a distinct website domain containing at least one backlink to another site.
Definition and useAnchor Text
Anchor text is the visible text or accessible label of a hyperlink.
Definition and useDomain Rating (DR)
Domain Rating is Ahrefs’ proprietary 0–100 metric estimating the relative strength of a website’s backlink profile.
Definition and useInternal Link
An internal link connects one page to another page on the same website or domain.
Definition and useFeatured Snippet
A featured snippet is a prominent Google result that extracts an answer from a web page and links to the source.
Definition and usePeople Also Ask (PAA)
People Also Ask is a Google search feature showing expandable related questions and sourced answers.
Definition and useRich Result
A rich result is an enhanced Google search appearance generated from supported page data and eligibility requirements.
Definition and use02
Technical SEO
8 definitions
Canonical Tag
A canonical tag is a rel="canonical" link element that identifies the preferred URL for duplicate or highly similar pages.
Definition and useDuplicate Content
Duplicate content is identical or substantially similar content available on more than one URL.
Definition and useHreflang
Hreflang annotations identify alternate language or regional versions of equivalent pages.
Definition and useSchema Markup
Schema markup is structured data using Schema.org vocabulary to describe page entities and facts in machine-readable form.
Definition and useCore Web Vitals
Core Web Vitals are field metrics for loading, responsiveness and visual stability: LCP, INP and CLS.
Definition and useCrawl Budget
Crawl budget is the set of limits and demand that influence how much Googlebot crawls a site over time.
Definition and useIndexability
Indexability describes whether a URL is eligible and suitable to be stored in a search engine’s index.
Definition and userobots.txt
robots.txt is a root-level text file that tells compliant crawlers which URL paths they may request.
Definition and use03
Content architecture
3 definitions
Topical Authority
Topical authority is an SEO industry concept describing how convincingly a site demonstrates expertise and useful coverage within a subject.
Definition and usePillar Page
A pillar page is a broad topic hub that introduces a subject and links to deeper supporting pages.
Definition and useContent Pruning
Content pruning is the evidence-led process of improving, consolidating, redirecting, archiving or removing pages that no longer justify their current form.
Definition and use04
AI search, GEO and entities
5 definitions
AEO (Answer Engine Optimization)
Answer engine optimization is the practice of making useful answers easy for search and AI systems to retrieve, verify, attribute and present.
Definition and useGEO (Generative Engine Optimization)
Generative engine optimization is the practice of improving how content and brands are retrieved, represented and cited in generative search answers.
Definition and useLLM Visibility
LLM visibility measures whether and how a brand, entity or source appears in answers generated by large language model products.
Definition and useEntity SEO
Entity SEO improves how search systems identify a real-world thing—such as an organization, person, place or product—and understand its relationships.
Definition and useKnowledge Graph
A knowledge graph is a structured network of entities, facts and relationships; Google uses one to support search understanding and knowledge features.
Definition and useFrom terminology to execution
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