23 terms, each with an example and a free check

The SEO glossary

Plain-English definitions of the technical terms you meet in audits and in Search Console, from 301 redirects to XML sitemaps.

301 redirectredirects and status codesAn HTTP status code that permanently moves a URL to a new location and tells search engines to index the new URL instead.302 redirectredirects and status codesAn HTTP status code for a temporary redirect: the URL has moved for now, but the original should stay indexed.307 redirectredirects and status codesA temporary HTTP redirect that, unlike 302, guarantees the browser repeats the request with the same method and body.

Anchor textlinksThe visible, clickable words of a hyperlink, which tell users and search engines what the linked page is about.

Broken linklinksA link that points to a page or file that no longer loads, typically returning a 404, 410 or server error.

Canonical tagmeta tags and on-page seoA link element, rel="canonical", that tells search engines which URL is the preferred version among duplicate or near-duplicate pages.

GPTBotai searchOpenAI's web crawler that collects publicly available pages that may be used to train its AI models.

Hreflangmeta tags and on-page seoAn HTML attribute that tells search engines which language and regional versions of a page exist, so each user sees the right one.

JSON-LDstructured dataJavaScript Object Notation for Linked Data: a format for adding schema.org structured data to a page inside a script tag.

llms.txtai searchA proposed Markdown file at /llms.txt that gives large language models a curated summary and link list of a website.

Meta descriptionmeta tags and on-page seoAn HTML meta tag that summarises a page; search engines often show it as the snippet under the title in results.Meta robots tagcrawling and indexingAn HTML meta tag in the page head that tells search engines whether to index the page, follow its links and how to show its snippet.

Nofollow linklinksA link with rel="nofollow", which tells search engines not to treat it as an endorsement or pass ranking credit through it.Noindexcrawling and indexingA directive, set in a robots meta tag or HTTP header, that tells search engines not to include a page in their results.

Open Graphmeta tags and on-page seoA set of meta tags, such as og:title and og:image, that control the title, description and image shown when a page is shared.

Redirect chainredirects and status codesA sequence of two or more redirects between the requested URL and the final page, such as A to B to C.Rich snippetsstructured dataSearch results enhanced with extra details, such as ratings, prices or breadcrumbs, drawn from a page's structured data.Robots.txtcrawling and indexingA plain-text file at the root of a website that tells crawlers which URLs they are allowed to fetch.

SERP featuresrankings and search resultsAny element on a search results page beyond the standard organic listings, such as featured snippets, AI Overviews or local packs.Soft 404redirects and status codesA URL that returns a 200 OK status but shows an error, an empty page or thin content, so Google treats it like a 404.

Title tagmeta tags and on-page seoThe HTML <title> element that names a page; search engines usually show it as the clickable headline of a result.

X-Robots-Tagcrawling and indexingAn HTTP response header that carries robots directives such as noindex, so they can apply to PDFs, images and other non-HTML files.XML sitemapcrawling and indexingA file in XML format that lists the URLs of a website you want search engines to discover, crawl and index.

From definition to fix

Knowing what a canonical tag or a redirect chain is only helps if you can find them on your own pages. The free SEO tools check one URL at a time, and the RareMatter SEO dashboard crawls your whole site every week and ranks every issue into one to-do list.

Questions

Frequently asked questions

Who is this SEO glossary for?

Site owners, marketers, freelancers and developers who meet an SEO term in an audit or in Search Console and want a straight explanation with an example they can copy.

How do I check these issues on my own website?

Every term links to a free RareMatter tool that tests it on any URL with no signup, from the robots.txt checker to the redirect checker and schema validator.

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