SEO GLOSSARY
The SEO glossary, explained properly.
Clear explanations of 43 SEO terms, technical concepts, search metrics and AI search terminology, with worked examples, ways to check them and the mistakes to avoid.
- Checked against primary sources
- Every entry dated and reviewed on a schedule
- Common mistakes on every entry
- 17 termsTechnical SEOStatus codes, redirects, canonicals and the other signals that decide what gets crawled and indexed.
- 14 termsCrawling, rendering & indexingHow crawlers discover, fetch and render pages, and the controls you have at each step.
- 13 termsOn-page SEO & contentTitles, descriptions, links and the content signals on the page itself.
- 11 termsSEO fundamentalsHow search engines find, rank and show pages, and the words every SEO conversation uses.
- 8 termsSearch analytics & measurementWhat Search Console and analytics count, and how the numbers relate to each other.
43
terms explained
16
topics
4
learning paths
48
primary sources cited
START HERE
Start with the terms that come up most.
The concepts behind almost every SEO conversation, report and audit.
- AI search & generative searchAI OverviewsGoogle’s AI-generated summaries above some search results, with links to source pages.Read the entry
- AI search & generative searchAI search visibilityHow a brand appears in AI answers: mentions, cited sources and referral visits are separate measures.Read the entry
- Backlinks & authorityBacklinkA link from another site to yours: a discovery path and a reputation signal.Read the entry
- Technical SEOCanonical tagA link element that names the preferred URL among duplicates; a strong hint, not a directive.Read the entry
- Search analytics & measurementClick-through rateClicks divided by impressions: how often a shown result was chosen.Read the entry
- Core Web Vitals & performanceCore Web VitalsGoogle’s three real-user metrics for loading (LCP), responsiveness (INP) and visual stability (CLS).Read the entry
- SEO tools, metrics & reportingGoogle Search ConsoleGoogle’s free first-party reports on a site’s search performance, indexing and crawling.Read the entry
- Crawling, rendering & indexingIndexingWhen a search engine stores a page so it can be shown in results; crawling does not guarantee it.Read the entry
- Internal linking & site architectureInternal linkingLinks between pages of the same site, which shape discovery, importance and navigation.Read the entry
- Crawling, rendering & indexingRobots.txtThe file at /robots.txt that tells crawlers which URLs not to fetch; it controls crawling, not indexing.Read the entry
- SEO fundamentalsSearch engine results pageThe page of results for a query: organic links, ads, AI answers, maps and other features.Read the entry
- Keyword research & search intentSearch intentThe goal behind a query, which decides what kind of page can satisfy it.Read the entry
- Structured data & search featuresStructured dataMachine-readable labels (usually Schema.org JSON-LD) that describe a page’s content.Read the entry
- On-page SEO & contentTitle tagThe page’s <title>: the main source of its clickable headline in search results.Read the entry
- Crawling, rendering & indexingWeb crawlerThe automated program that fetches pages and follows links for a search engine, AI service or tool.Read the entry
BROWSE BY TOPIC
Browse by what you are working on.
Each topic opens the A–Z list filtered to its terms. Some terms belong to more than one.
SEO fundamentals
How search engines find, rank and show pages, and the words every SEO conversation uses.
Technical SEO
Status codes, redirects, canonicals and the other signals that decide what gets crawled and indexed.
Crawling, rendering & indexing
How crawlers discover, fetch and render pages, and the controls you have at each step.
On-page SEO & content
Titles, descriptions, links and the content signals on the page itself.
Keyword research & search intent
What people search for, and the intent behind a query.
Search analytics & measurement
What Search Console and analytics count, and how the numbers relate to each other.
Core Web Vitals & performance
The loading, responsiveness and visual stability metrics Google measures on real visits.
Internal linking & site architecture
How internal links and site structure spread discovery and importance.
Backlinks & authority
Links from other sites, the attributes on them and what they signal.
Local SEO
Map results and the signals behind local rankings.
E-commerce SEO
Filters, product pages and the crawl traps online stores create.
AI search & generative search
AI Overviews, AI crawlers and how brands appear in AI answers.
Structured data & search features
Schema markup and the rich results it can make a page eligible for.
SEO auditing & troubleshooting
Logs, error reports and the checks that find what is broken.
SEO tools, metrics & reporting
The platforms and metrics used to measure and report on SEO.
International & multilingual SEO
Serving the right language or country version of a page.
ALL TERMS
Every term, A to Z.
43 terms, alphabetically. Filter by topic to narrow the list.
Filter by topic
A
- AI crawlersBots that fetch pages for AI training, AI search indexes or live user requests.
- AI OverviewsGoogle’s AI-generated summaries above some search results, with links to source pages.
- AI search visibilityHow a brand appears in AI answers: mentions, cited sources and referral visits are separate measures.
- Anchor textThe clickable words of a link, read by search engines as a description of the target page.
- Average positionSearch Console’s impression-weighted average of your topmost result position.
B
- BacklinkA link from another site to yours: a discovery path and a reputation signal.
C
- Canonical tagA link element that names the preferred URL among duplicates; a strong hint, not a directive.
- Click-through rate CTRClicks divided by impressions: how often a shown result was chosen.
- Core Web Vitals CWVGoogle’s three real-user metrics for loading (LCP), responsiveness (INP) and visual stability (CLS).
- Crawl budgetHow many URLs a search engine is able and willing to crawl on a site; a concern mainly for large sites.
- Crawl logsServer or CDN request records filtered to bots: what crawlers really fetched and received.
- Cumulative Layout Shift CLSHow much content jumps around unexpectedly; good is 0.1 or less.
D
- Duplicate contentThe same or near-identical content at several URLs; usually a canonicalization issue, not a penalty.
E
- E-E-A-TExperience, expertise, authoritativeness and trust: Google’s rater framework for page quality.
F
- Faceted navigationListing filters that can generate huge numbers of near-duplicate URLs.
G
- Generative engine optimization GEOAn emerging, non-standard label for optimising to be mentioned and cited in AI answers.
- Google Search Console GSCGoogle’s free first-party reports on a site’s search performance, indexing and crawling.
H
- HreflangAnnotations that connect language and country versions of the same page.
- HTTP status codesThe three-digit code a server returns with each response, which crawlers act on before reading the page.
I
- ImpressionsHow often a link to your site appeared in search results, as counted by Search Console.
- IndexingWhen a search engine stores a page so it can be shown in results; crawling does not guarantee it.
- Interaction to Next Paint INPHow quickly a page visibly responds to taps, clicks and typing; good is 200 ms or less.
- Internal linkingLinks between pages of the same site, which shape discovery, importance and navigation.
K
- Keyword cannibalizationSeveral of your own pages competing for the same intent, so none performs as well as one would.
L
- Largest Contentful Paint LCPWhen the main image or text block appears; good is 2.5 seconds or less.
- llms.txtA proposed Markdown file that summarises a site for language models; not a standard.
- Local packThe map and short list of businesses Google shows for local searches.
M
- Meta descriptionA short page summary that Google may show as the result snippet; it affects clicks, not rankings.
N
R
- RenderingRunning a page’s code to build the final content a search engine indexes.
- Rich resultsSearch results enhanced with prices, ratings, images or other details, usually from structured data.
- Robots.txtThe file at /robots.txt that tells crawlers which URLs not to fetch; it controls crawling, not indexing.
S
- Search engine results page SERPThe page of results for a query: organic links, ads, AI answers, maps and other features.
- Search intentThe goal behind a query, which decides what kind of page can satisfy it.
- Soft 404A not-found or empty page that wrongly returns 200 OK.
- Structured dataMachine-readable labels (usually Schema.org JSON-LD) that describe a page’s content.
T
- Time to First Byte TTFBHow long the server takes to start answering; a diagnostic that feeds LCP.
- Title tagThe page’s <title>: the main source of its clickable headline in search results.
W
- Web crawlerThe automated program that fetches pages and follows links for a search engine, AI service or tool.
X
- XML sitemapA machine-readable list of the URLs you want search engines to discover.
#
- 301 redirectA permanent move from one URL to another; the standard way to change URLs without losing search visibility.
- 404 error 404The Not Found response for a URL with no page; correct for dead URLs, a problem only for ones that matter.
No terms in this topic yet.
LEARNING PATHS
Read these in order.
Short sequences of entries that build on each other.
How Google finds pages
From the first request to a place in the index, and the controls you have at each step.
Website performance
Server response first, then the three metrics Google uses for real-user experience.
Reading search performance data
What Search Console counts, and how the numbers relate to each other.
AI search
Who fetches your pages for AI, where answers appear, and how to measure what you get from them.
LEARN & TRY
Guides and free tools for the same job.
The glossary explains the concepts. The guides walk through a task, and the free tools run the checks.
How indexing really works
Discovery, crawling, inspection and indexing are separate steps, with separate evidence.
Prioritise a technical audit
Fix the issues on pages that earn search attention first.
Mentions, citations and visits
Three AI search signals that answer different questions.
Your data vs market estimates
Which questions first-party data and provider estimates can each answer.
Free SEO tools
Checkers and generators for robots.txt, canonicals, sitemaps, structured data, snippets and AI crawlers. No sign-up.
Crawler directory
Every major search, AI and SEO crawler, with its user agent and robots.txt token.
FAQ
About the SEO glossary.
How the entries are written, checked and kept current.
How are the entries written and checked?
Each entry is written by Ndovu SEO Labs and checked against primary sources: Google Search Central, Search Console Help, web.dev, IETF RFCs, Schema.org and the documentation of the companies that run the crawlers and tools described. The sources are listed at the end of every entry.
How often is an entry reviewed?
On a schedule set by how fast the subject changes: every three months for AI search, every six months for Google reporting and features, and yearly for stable technical standards. The reviewed date changes when a check is done; the updated date changes only when the content does.
Are the examples real?
Examples use made-up sites and illustrative numbers unless a source is named. We do not present invented data as real results.
Why is a term missing?
Concepts we have not finished writing are not published, and emerging or disputed terms are described as such. Many related phrases already lead to the entry that covers them, so try the broader concept in the search box.
How do I report a mistake?
Write to us through the contact page and name the entry. Corrections are checked against the sources, and the entry’s reviewed date changes when the check is done.
See these concepts in your own data.
The NdovuSEOLabs platform connects your Search Console, analytics and server logs, so crawling, indexing and Core Web Vitals show up for your own pages.