SEO Glossary
Plain-English explanations of SEO terminology, metrics, technical signals and search features. Use this glossary when a report, tool or SEO discussion uses a term you want to understand before taking action.
Problem fixes and how-to guides
GuideCanonical URLThe canonical URL is the preferred URL for a page when multiple URLs contain duplicate or substantially similar content. It is a…GuideCrawlabilityCrawlability describes whether a search engine crawler can discover and fetch a URL and its required resources. A page can be…GuideIndexabilityIndexability is a page’s technical eligibility to be considered for a search index. Eligibility does not guarantee that a search…GuideRobots.txtrobots.txt is a site-level text file that gives compliant crawlers instructions about which URL paths they may request. It is…GuideXML SitemapAn XML sitemap lists preferred URLs that a site wants search engines to discover. It is a discovery aid, not an indexing command.GuideHreflangHreflang annotations identify alternate language or regional versions of a page. Correct implementation uses valid locale values…GuideHTTP Status CodeAn HTTP status code communicates the result of a request. Common SEO-relevant examples include 200 for success, 301/308 for…GuideRedirect ChainA redirect chain occurs when a requested URL passes through multiple redirects before reaching the final destination. Extra hops…GuideSoft 404A soft 404 is a page that appears to be missing or empty but returns a success-like HTTP response. It can confuse crawlers about…GuideOrphan PageAn orphan page is a URL with no discoverable internal link path from the crawl starting point or known site structure. The term…GuideCrawl DepthCrawl depth is the number of link steps from a chosen starting URL to a discovered page. It depends on the crawl entry point and…GuideCore Web VitalsCore Web Vitals are user-experience metrics covering loading performance, interactivity and visual stability. The current core…GuideLargest Contentful Paint (LCP)LCP measures the render time of the largest content element visible in the viewport. It is primarily a loading-performance metric.GuideInteraction to Next Paint (INP)INP measures responsiveness across qualifying user interactions during a page visit. It reflects the delay until the next visual…GuideCumulative Layout Shift (CLS)CLS measures unexpected visual movement during a page visit. Late-loading media, injected components and font changes can…GuideStructured DataStructured data is machine-readable markup that describes entities and page content. JSON-LD is a common format, but valid…GuideTitle TagThe title element provides a document title and can contribute to the title link shown in search results. Search engines may…GuideMeta DescriptionA meta description summarizes a page and may be used as the search snippet. Search engines can choose other page text instead.GuideAnchor TextAnchor text is the visible clickable text of a link. Descriptive wording helps visitors understand the destination and provides…GuideReferring DomainA referring domain is a distinct domain that contains at least one link to the site being analyzed. It is different from the…GuideNofollowThe rel="nofollow" attribute indicates that a publisher does not want to imply a normal endorsement relationship. Search engines…GuideThird-party Domain Authority MetricsDomain Authority, Domain Rating and similar metrics are third-party estimates created by SEO providers. They are not Google…GuideSearch IntentSearch intent is the task or need behind a query, such as learning, comparing, finding a specific site or completing a…GuideKeyword CannibalizationKeyword cannibalization describes situations where multiple pages compete for similar queries. Overlap alone is not proof of…GuideSERPA search engine results page (SERP) is the page shown after a user submits a query. It can contain organic listings, ads, maps…GuideClick-Through Rate (CTR)CTR is the proportion of impressions that result in clicks. Search Console CTR is clicks divided by impressions for the selected…GuideAI Search VisibilityAI search visibility describes how often a brand, page or source is mentioned or cited in AI-generated search experiences…Guidellms.txtllms.txt is an emerging, optional convention for publishing a curated text-oriented map of useful site resources for AI systems…GuideUTM ParametersUTM parameters are query-string values used to identify campaign source, medium, name and related attribution information in…GuideCanonicalizationCanonicalization is the process of selecting a preferred URL among duplicate or similar URL variants. Search engines consider…GuideMobile-First IndexingMobile-first indexing means Google primarily uses the mobile version of a site’s content for indexing. Important content and…GuideE-E-A-TE-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness. It is a framework used in Google’s quality…GuideCrawl TrapA crawl trap is a site structure or URL pattern that can lead crawlers through an excessive or effectively unbounded set of…GuideCanonical HintA canonical annotation suggests which URL should represent duplicate or substantially similar content. Search engines can select…GuideAlt TextAlternative text provides a text equivalent for an image’s information or function. Decorative images should generally use an…GuideBacklinkA backlink is a hyperlink from another website to a page on your site. Its value depends on context, relevance, editorial intent…GuideLocalBusiness SchemaLocalBusiness structured data describes eligible real-world businesses and their details. The information should be accurate and…GuideField DataField data is performance information collected from real users in real browsing conditions. It can vary by device, network…GuideLab DataLab data comes from a controlled performance test using a defined device and network configuration. It is useful for reproducing…