126 terms an SEO professional is expected to know, defined plainly and grouped by the part of the job they belong to. This is written for people building a career rather than for a general audience: every definition is framed around what the concept means when you have to use it, explain it to a stakeholder, or defend it in an interview.
20 of the terms have full guides behind them, covering why the skill matters commercially, what the work involves, how it comes up in interviews and what goes wrong most often.
Terms with full career guides
Answer Engine Optimization (AEO) — A closely related term emphasising direct-answer surfaces: AI Overviews, assistants and chat-based search. Used intercha…
Content audit — A systematic review of every page on a site against performance, intent match and business value, ending in a decision t…
Core Web Vitals — Google's set of user-experience metrics: Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift…
Crawl budget — The number of URLs a search engine is willing to crawl on a site in a given period, set by crawl rate limits and crawl d…
Digital PR — Earning coverage and links by creating something genuinely newsworthy — original data, research, tools or commentary — a…
E-E-A-T — Experience, Expertise, Authoritativeness and Trust — the framework in Google's quality rater guidelines. Not a direct ra…
Generative Engine Optimization (GEO) — Optimising to be surfaced and cited inside AI-generated answers rather than only in classic results. The fastest-growing…
Internal linking — Links between pages on the same site. The main mechanism a site owner directly controls for distributing authority and s…
International SEO — Running search across multiple countries and languages: hreflang, market-level content strategy, and cross-border duplic…
Keyword research — Identifying the queries an audience uses, estimating their volume and difficulty, and grouping them into pages worth bui…
Link building — The practice of earning links from other sites. Modern practice divides between digital PR and relationship-driven outre…
Local SEO — Optimising for location-based queries and map results. A distinct discipline with its own ranking factors, tooling and f…
Log file analysis — Reading server logs to see exactly which URLs search engine bots requested, when, and with what response. The only sourc…
Programmatic SEO — Generating large numbers of pages from a structured data source against a repeatable template and query pattern. Powerfu…
Search intent — What a searcher is actually trying to accomplish: to learn, to find a specific site, to compare, or to buy. Matching int…
Share of voice — The proportion of total available search visibility a site captures across a defined keyword set, weighted by volume and…
Site migration — Any change to a site's domain, URL structure, platform, design or content organisation that affects how search engines s…
Structured data — Machine-readable markup, usually JSON-LD following schema.org vocabulary, that describes what a page is about. It powers…
Technical SEO — The discipline of making a site crawlable, indexable, renderable and fast enough that search engines can access and unde…
Topical authority — The degree to which a site is recognised as a comprehensive, credible source on a subject, built through depth of covera…
Frequently asked questions
How many SEO terms do I actually need to know for an interview?
Far fewer than are listed here. Interviewers test depth on a handful of concepts rather than breadth across many. Know search intent, indexation, internal linking, Core Web Vitals and how you measure success properly, and you will handle most screens. Memorising definitions without being able to apply them is transparent to any experienced interviewer.
What is the difference between GEO and AEO?
In practice, very little. GEO emphasises generative AI answer systems; AEO covers direct-answer surfaces more broadly, including featured snippets that predate AI. Most employers use them interchangeably, so treat a job advert mentioning one as mentioning both. See GEO and AEO.
Is E-E-A-T a ranking factor?
No, and saying it is will cost you credibility in an interview. It is a framework from Google's quality rater guidelines describing what the ranking systems try to approximate. The distinction matters. See E-E-A-T.
Which of these terms should I learn first?
Search intent, indexation and internal linking. Those three explain most of why pages do or do not rank, and everything else builds on them. After that, pick a specialism: technical SEO has the strongest pay evidence behind it.
Figures on this page are aggregated market estimates compiled from the sources above and are intended for orientation, not as an offer, guarantee or valuation. See our salary data methodology.
Technical SEO (34 terms)
Cannibalisation
Two or more pages on the same site competing for the same query, splitting signals and producing unstable rankings for both.
Canonical tag
A link element declaring the preferred URL among a set of duplicate or near-duplicate pages. It is a strong hint rather than a directive, and search engines can ignore it.
Client-side rendering (CSR)
Building the page in the browser with JavaScript. Workable for SEO but higher-risk, because it depends on the crawler successfully executing your code.
Google's set of user-experience metrics: Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift. They are a real ranking input, but a small one relative to relevance.
The number of URLs a search engine is willing to crawl on a site in a given period, set by crawl rate limits and crawl demand. It only becomes a practical constraint on large sites.
Crawling
The process by which a search engine's bot discovers URLs by following links and reading sitemaps. A page that is never crawled can never be indexed.
Cumulative Layout Shift (CLS)
A measure of unexpected visual movement during page load, usually caused by images or ads without reserved space.
Duplicate content
Substantially identical content available at more than one URL. Rarely a penalty; usually a consolidation and crawl-efficiency problem.
Faceted navigation
Filter and sort controls on category pages. Left unmanaged they generate near-infinite URL combinations and are one of the most common causes of index bloat in e-commerce.
hreflang
Annotations telling search engines which language and regional version of a page to serve to which audience. Difficult to implement correctly at scale and easy to break.
HTTPS
Encrypted transport for a site. A lightweight ranking signal and a baseline expectation; its absence is now a trust problem more than a ranking one.
Hydration
Attaching JavaScript behaviour to server-rendered HTML in the browser. Poor hydration is a common cause of INP problems on modern frameworks.
Index bloat
A large number of low-value URLs in the index — parameters, filters, tag archives, thin pages — diluting a site's overall quality signals and wasting crawl.
Indexing
Storing and organising a crawled page so it can be returned in results. Being crawled does not guarantee being indexed: search engines routinely decline to index pages they judge low-value or duplicative.
Interaction to Next Paint (INP)
A responsiveness metric measuring the delay between a user interaction and the next visual update. It replaced First Input Delay as a Core Web Vital in 2024.
JSON-LD
The JSON-based syntax Google recommends for structured data. It sits in a script tag and is decoupled from the visible markup, which makes it easier to maintain.
Largest Contentful Paint (LCP)
The time until the largest visible element in the viewport finishes rendering. The practical target is under 2.5 seconds at the 75th percentile of real users.
Reading server logs to see exactly which URLs search engine bots requested, when, and with what response. The only source of ground truth about crawl behaviour.
Meta robots tag
A page-level directive (noindex, nofollow, max-snippet and others) that controls how a page may be indexed and displayed. Unlike robots.txt it requires the page to be crawlable to work.
Mobile-first indexing
Google's use of the mobile version of a page as the primary basis for indexing and ranking. Content missing from the mobile version is effectively missing.
Orphan page
A page with no internal links pointing to it. Hard to discover, hard to rank, and usually a symptom of a broken template or a stale CMS.
Pagination
How a sequence of pages in a series is structured and linked. Google no longer supports rel=next/prev, so pagination now depends on clean internal linking and crawlable links.
Redirect (301 / 302)
An HTTP response sending a request to a different URL. A 301 signals a permanent move and consolidates signals; a 302 signals a temporary one and is often treated differently.
Redirect chain
Two or more redirects between the requested URL and the final destination. Chains waste crawl resource, slow users down, and risk signal loss at each hop.
Rendering
The step where a crawler executes JavaScript and constructs the final DOM. Content that only appears after rendering is discovered later and less reliably than content in the initial HTML.
Rich result
A search result enhanced with extra features — review stars, FAQs, product prices, breadcrumbs — generated from structured data.
Robots.txt
A file at the root of a domain that tells crawlers which paths they may request. It controls crawling, not indexing — a blocked URL can still be indexed if other pages link to it.
Server-side rendering (SSR)
Generating the full HTML on the server before sending it to the browser. Generally the safest approach for SEO on JavaScript-heavy stacks.
Any change to a site's domain, URL structure, platform, design or content organisation that affects how search engines see it. The highest-risk project in SEO.
Soft 404
A page that returns a 200 status but contains no meaningful content, or an error message. Search engines detect these and treat them as errors regardless of the status code.
Status code
The three-digit HTTP response accompanying every request: 200 for success, 301 and 302 for redirects, 404 for not found, 410 for gone, 5xx for server errors. Auditing them is the first step in almost any technical diagnosis.
Machine-readable markup, usually JSON-LD following schema.org vocabulary, that describes what a page is about. It powers rich results and helps entity understanding.
The discipline of making a site crawlable, indexable, renderable and fast enough that search engines can access and understand every page you want them to. It covers architecture, indexation control, performance, structured data and migrations.
XML sitemap
A machine-readable list of a site's canonical URLs submitted to search engines to aid discovery. It supplements internal linking rather than replacing it.
Content & on-page (25 terms)
Anchor text
The visible, clickable text of a link. It tells both users and search engines what the destination is about.
A systematic review of every page on a site against performance, intent match and business value, ending in a decision to keep, improve, consolidate or remove.
Content brief
A specification for a piece of content: target query, intent, angle, required sections, sources, internal links and success criteria. The main quality-control lever in content production.
Content decay
The gradual decline of a page's traffic as competitors update, intent shifts, or the information ages. Managing decay is often more valuable than publishing new content.
Content pruning
Removing or consolidating low-value pages to concentrate quality signals and crawl on the pages that matter. Frequently one of the highest-return actions on a large old site.
Cornerstone content
The small set of pages a site most wants to rank, prioritised in internal linking and maintenance.
Entity
A distinct thing — a person, company, place, product, concept — that a search engine can recognise and relate to other things. The unit of modern search understanding.
Featured snippet
An extracted answer displayed above the standard results. Winning one requires directly answering the question in a concise, extractable format near the top of the page.
Heading hierarchy
The H1–H6 structure of a page. It communicates document outline to assistive technology and to extraction systems, which matters increasingly for AI answer citation.
Links between pages on the same site. The main mechanism a site owner directly controls for distributing authority and signalling importance.
Keyword difficulty
A tool-specific score estimating how hard it is to rank for a query, usually derived from the link profiles of current top results. Directional at best.
Identifying the queries an audience uses, estimating their volume and difficulty, and grouping them into pages worth building. The foundation of any content strategy.
Knowledge graph
A search engine's structured database of entities and the relationships between them, used to power knowledge panels and to disambiguate queries.
Long-tail keyword
A longer, more specific query with lower volume and usually lower competition. Collectively long-tail queries account for the majority of all searches.
Meta description
A summary element that has no direct ranking effect but influences click-through when used as the snippet.
People Also Ask
The expandable question box in Google results. A useful, free source of related intents and subtopics for content planning.
Pillar page
A comprehensive page covering a broad topic and linking out to the more specific pages beneath it. The anchor of a topic cluster.
Generating large numbers of pages from a structured data source against a repeatable template and query pattern. Powerful when the underlying data is genuinely useful, and a fast route to index bloat when it is not.
What a searcher is actually trying to accomplish: to learn, to find a specific site, to compare, or to buy. Matching intent is the single largest determinant of whether a page can rank at all.
Search volume
An estimate of how often a query is searched per month. Every tool's figure is modelled, not measured, and they routinely disagree by a factor of two or more.
Semantic search
Search that interprets meaning and relationships between entities rather than matching strings. It is why exact-match keyword density stopped mattering years ago.
Thin content
A page with little substantive value relative to the query it targets. A quality problem rather than a word-count problem.
Title tag
The HTML element defining a page's title, used as the primary basis for the clickable headline in results. Google rewrites it roughly a third of the time.
Topic cluster
A pillar page covering a broad subject linked to a set of deeper pages covering its components, all interlinked. A structural approach to demonstrating topical coverage.
The degree to which a site is recognised as a comprehensive, credible source on a subject, built through depth of coverage, internal structure and external corroboration.
Links & authority (13 terms)
Backlink
A link from another site to yours. Still one of the strongest external signals of credibility, though quality and relevance matter far more than count.
Broken link building
Finding dead links on other sites and offering your own resource as a replacement. Low yield but genuinely white-hat.
Earning coverage and links by creating something genuinely newsworthy — original data, research, tools or commentary — and pitching it to journalists.
Disavow
Telling Google to ignore specified links to your site. A tool of last resort, appropriate mainly when facing a manual action for link schemes.
Domain authority / rating
Third-party scores from Moz, Ahrefs and Semrush estimating a domain's link strength. Useful for relative comparison; not used by Google and not a ranking factor.
Guest posting
Writing content for another site, historically in exchange for a link. Legitimate when the content is genuinely good and the audience is real; a link scheme when it is a transaction at scale.
The practice of earning links from other sites. Modern practice divides between digital PR and relationship-driven outreach on one side, and increasingly penalised transactional tactics on the other.
Link equity
The value passed from one page to another through a link. Distributed through both external backlinks and internal linking.
Link velocity
The rate at which a site acquires new links over time. Sharp unnatural spikes can attract scrutiny.
Nofollow
A link attribute indicating the linking site does not vouch for the destination. Now treated as a hint rather than a directive.
Sponsored / UGC attributes
Link attributes marking paid placements and user-generated content respectively. Correct labelling is the compliant way to carry commercial and community links.
Toxic backlink
A link from a spammy or manipulative source. Google is generally good at ignoring these; aggressive disavowing does more harm than good in most cases.
Unlinked mention
A reference to your brand without a link. Converting these is usually the easiest link acquisition available to an established brand.
Measurement & analytics (14 terms)
A/B testing (SEO)
Splitting page templates rather than users to measure the search impact of a change, since conventional user-splitting does not work for crawlers.
Attribution
Assigning credit for a conversion across the touchpoints that preceded it. Organic search is systematically undercredited by last-click models.
Average position
The mean ranking position across impressions. Heavily distorted by averaging across queries and pages; useful only when tightly filtered.
Click-through rate (CTR)
Clicks divided by impressions. Falling CTR at stable position is one of the clearest signals of AI answers absorbing clicks.
Cohort analysis
Grouping pages or users by a shared characteristic — publication date, template, intent type — to isolate what is actually driving a change.
Forecasting
Projecting the traffic and revenue impact of planned SEO work. The skill that most reliably separates senior practitioners from mid-level ones in interviews.
GA4
Google Analytics 4, the current event-based analytics platform. Its data model differs fundamentally from Universal Analytics, which is why historical comparisons often mislead.
Google Search Console
Google's free property-level reporting on impressions, clicks, position, indexation and page experience. The only first-party source of query data, and non-negotiable for any SEO role.
Impressions
The number of times a site's result appeared for a query. In Search Console an impression is counted even without a scroll into view in some result types.
Organic session
A visit originating from unpaid search results, as recorded by an analytics platform.
Rank tracking
Monitoring positions for a defined keyword set over time. Increasingly imprecise as results personalise and diversify, but still useful directionally.
SERP
Search engine results page. Modern SERPs contain AI answers, ads, packs and panels alongside the classic blue links, which is why position alone no longer predicts traffic.
The proportion of total available search visibility a site captures across a defined keyword set, weighted by volume and position.
Zero-click search
A search resolved on the results page without a click to any site. The share of these has risen sharply with AI Overviews.
AI search & GEO (11 terms)
AI content detection
Attempts to identify machine-generated text. Google's stated position is that it rewards quality regardless of production method and penalises scaled low-value content regardless of who wrote it.
AI Overviews
Google's AI-generated summaries at the top of many results, assembled from multiple sources and displacing traditional listings.
A closely related term emphasising direct-answer surfaces: AI Overviews, assistants and chat-based search. Used interchangeably with GEO by most employers.
Chunking
Splitting content into passages for retrieval. Content with clear headings, self-contained sections and direct answers chunks better and is therefore more citable.
Citation (AI)
A source reference inside an AI-generated answer. Increasingly tracked as a visibility metric in its own right, separate from rankings.
Entity optimisation
Making a brand or subject unambiguously recognisable to knowledge systems through consistent naming, structured data and corroborating external references.
Optimising to be surfaced and cited inside AI-generated answers rather than only in classic results. The fastest-growing skill requirement in SEO job adverts.
LLM
Large language model — the class of system behind AI search answers and assistants. Understanding how they retrieve and cite sources is now part of the SEO job.
llms.txt
A proposed plain-text file describing a site's key content for large language models, analogous in spirit to robots.txt. Adoption is voluntary and support is inconsistent.
Prompt engineering
Designing inputs to get reliable output from a language model. A practical productivity skill in SEO workflows rather than a discipline of its own.
Retrieval-augmented generation (RAG)
Grounding an AI answer in retrieved documents rather than model memory. The mechanism that makes citation, and therefore GEO, possible.
Careers, hiring & the industry (19 terms)
Agency SEO
Working on multiple client accounts. Faster learning curve and broader exposure, usually at lower pay for the same tenure.
Black hat SEO
Tactics that violate search engine guidelines. The economics stopped working for most legitimate businesses years ago; the downside risk is asymmetric.
Core update
A broad, periodic change to Google's ranking systems. Recovery generally requires substantive improvement rather than tactical fixes.
Experience, Expertise, Authoritativeness and Trust — the framework in Google's quality rater guidelines. Not a direct ranking factor, but a good description of what the ranking systems try to approximate.
Freelance SEO
Independent practice, billing clients directly. Higher effective rates, no benefits, and an income constrained by sales rather than skill.
Geographic pay band
A location-adjusted salary range applied to remote roles. Increasingly the default at mid-size and larger employers.
Head of SEO
Leadership role accountable for organic search as a business line, typically reporting into marketing or growth leadership.
In-house SEO
Working on one company's own properties, with deeper context and longer horizons but narrower variety.
Manual action
A human-issued penalty applied to a site for guideline violations, visible in Search Console and requiring a reconsideration request to lift.
Pay band
The published or internal salary range for a level. Asking which band an offer sits in, and where in it, is more productive than negotiating a single number.
Portfolio (SEO)
Documented evidence of work and outcomes. Weighs more heavily than certifications in almost every SEO hiring process.
Quality rater guidelines
Google's public document instructing human evaluators how to assess result quality. The closest thing to an official statement of what Google is aiming for.
SEO audit
A structured diagnostic of a site's search performance and the constraints on it. The standard deliverable in consulting and a common interview task.
SEO manager
A role owning the organic channel: strategy, roadmap, budget and usually a team or agency relationships.
SEO specialist
The most common SEO job title, covering on-page work, content planning and first-line technical diagnosis. Scope varies enormously by employer.
Take-home task
An unpaid or paid exercise in an SEO interview process, usually a mini audit or strategy outline. Reasonable at a few hours; a red flag beyond that.
Total compensation
Base salary plus bonus, equity, pension or retirement contributions, healthcare and benefits. The only meaningful basis for comparing offers.
White hat SEO
Practice that works with search engine guidelines rather than against them, on the premise that durable rankings come from genuinely better pages.
YMYL
Your Money or Your Life — topics that could affect health, finances or safety, held to a higher quality bar in Google's rater guidelines.
Local & international (10 terms)
ccTLD
A country-code top-level domain such as .de or .fr. A strong geo-targeting signal and an expensive structural commitment.
Citation (local)
A mention of a business's NAP details on a third-party directory, used as a corroborating signal for local ranking.
Geo-targeting
Signalling which country a piece of content is intended for, through hreflang, domain structure, hosting and content localisation.
Google Business Profile
The listing that controls a business's presence in Google Maps and local results. The single most important asset in local SEO.
Optimising for location-based queries and map results. A distinct discipline with its own ranking factors, tooling and failure modes.
Map pack
The block of three local business results with a map, shown for queries with local intent.
NAP consistency
Keeping name, address and phone number identical across every directory and citation. Inconsistency is the most common cause of weak local visibility.
Service area business
A business that serves customers at their location rather than its own, with distinct Google Business Profile rules.
Subdirectory vs subdomain
The two common structures for international or sectioned content. Subdirectories generally consolidate authority more effectively; subdomains are sometimes required by platform constraints.