Hreflang & International SEO Glossary

International SEO has its own vocabulary. This glossary covers the terms you'll encounter when implementing hreflang, configuring multi-regional sites, or debugging international search issues. For a structured walkthrough of hreflang from start to finish, see our comprehensive hreflang guide.

Alternate Tag

The HTML element used to declare hreflang relationships: <link rel="alternate" hreflang="..." href="...">. The rel="alternate" attribute signals this is a variant of the current page; the hreflang attribute specifies which locale that variant targets. See hreflang HTML examples for copy-paste templates.

Canonical Tag

<link rel="canonical" href="..."> -- tells search engines which URL is the authoritative version of a page. On multilingual sites, each language page should have a self-referencing canonical (pointing to itself), not a canonical pointing to the primary language version. Read more about how these two tags interact in hreflang and canonical tags.

ccTLD (Country-Code Top-Level Domain)

A domain suffix that signals a specific country: .fr for France, .de for Germany, .co.uk for the UK. ccTLDs are the strongest geographic signal available in international SEO -- stronger than subdirectories or subdomains. The tradeoff is separate domain registration, separate GSC properties, and more complex link equity management. You can verify your domain configuration with a DNS record check.

Cluster (Hreflang Cluster)

The full set of pages connected by hreflang annotations. If your site has English, French, and German versions of a page, those three URLs form a cluster. Every page in the cluster must link to every other page in the cluster -- including itself. Missing any of these links creates a return link error.

Geotargeting

Configuring signals that tell search engines which country a site or page targets. Methods include: ccTLD, Google Search Console country targeting settings, IP address, and hreflang region codes. Hreflang is the most precise tool for combining language and region targeting. Google's documentation covers the supported signals.

Hreflang

An HTML attribute that tells search engines which language and optionally which region a page is intended for, and how it relates to equivalent pages in other languages or regions. Hreflang is a signal, not a directive -- Google uses it as strong guidance but isn't obligated to follow it. Learn more in what is hreflang.

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i18n (Internationalization)

Short for "internationalization" (18 letters between the i and n). The process of designing software or content so it can be adapted for multiple languages and regions without engineering changes for each locale. Related but distinct from localization (l10n).

ISO 639-1

The international standard for two-letter language codes used in hreflang: en for English, fr for French, de for German, zh for Chinese. Always lowercase in hreflang attributes. The full code list is maintained at loc.gov. See our hreflang language codes reference for common codes and gotchas.

ISO 3166-1 Alpha-2

The international standard for two-letter country codes used in hreflang region tags: US, GB, AU, FR, DE. Always uppercase in hreflang attributes. Combined with ISO 639-1: en-GB, fr-FR, zh-TW. The full list is at iso.org.

Lang Attribute

The HTML lang attribute on the <html> element: <html lang="fr">. This is a separate signal from hreflang -- it tells browsers and screen readers what language the current page is in. It doesn't affect hreflang behavior directly but is a best-practice complement to hreflang implementation.

Localization (l10n)

Adapting content for a specific locale -- not just translating words, but adjusting currency, date formats, units of measurement, cultural references, and legal requirements. Localized pages are better candidates for hreflang than machine-translated ones.

Multilingual Site

A site that serves content in more than one language. Multilingual sites are the primary use case for hreflang. Platform-specific guides are available for WordPress, Shopify, and Magento.

Multi-Regional Site

A site that targets users in multiple countries, potentially in the same language. A US and UK English site is multi-regional even if it's not multilingual. Multi-regional sites often benefit from hreflang with region codes (en-us, en-gb). See do you need hreflang for a single language site for guidance.

Return Link

The requirement that every page in a hreflang cluster must include hreflang annotations pointing to all other pages in the cluster. If page A points to page B via hreflang, page B must point back to page A. Missing return links cause Google to discount or ignore the hreflang signal. See hreflang missing return links for causes and fixes.

Self-Referencing Hreflang

Each page in a hreflang cluster must include a hreflang tag pointing to itself. If your French page only lists alternates for English and German but not itself, the implementation is incomplete. Self-referencing confirms to Google that this URL is an intentional member of the cluster. Read our self-referencing hreflang article for details.

Subdirectory (Language Subdirectory)

Using URL path segments to separate language versions: example.com/en/, example.com/fr/. This is the most common and recommended URL structure for multilingual sites -- it keeps everything on one domain while making language clear in the URL.

Subdomain (Language Subdomain)

Using subdomains to separate language versions: en.example.com, fr.example.com. Technically treated as separate sites by some systems, but Google considers them part of the same domain for hreflang purposes. More complex to manage than subdirectories.

x-default

A special hreflang value (hreflang="x-default") that designates the fallback page shown to users who don't match any specific locale. Typically points to your English or global homepage, or to a language selector page. Every hreflang cluster should include one x-default tag. See our x-default guide for implementation details.

xhtml:link

The element used to declare hreflang in XML sitemaps, as opposed to HTML <link> elements. Requires the xmlns:xhtml namespace declaration. Functions identically to HTML hreflang from Google's perspective -- pick one method and use it consistently. See hreflang in XML sitemaps for syntax and examples.

XML Sitemap

A structured file that lists URLs on your site and their metadata. Hreflang can be declared in XML sitemaps as an alternative to HTML <link> tags. Useful for large sites where adding head tags to every page is impractical. For guidance on combining hreflang with sitemaps, see our sitemap hreflang guide and this external hreflang sitemaps resource.

References

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