Cache header A cache header is the server response header that tells the browser how long a resource may be stored and how it is to be revalidated. Performance

Canonical address A canonical address is the markup declaring which page is the original when the same or very similar content is reachable from more than one address. Multilingual

Citation A citation is an answer engine mentioning a source in the answer it produces, usually with a link to it. Answer engines

CLS (Cumulative Layout Shift) measures how much content shifts unexpectedly while a page is loading or in use, and Google counts anything under 0.1 as good. Performance

Colour blindness is the inability to tell certain colours apart, and it affects a considerable share of the world’s population, men in particular. Accessibility

Compression is the shrinking of text-based resources before they are sent from the server and their expansion in the browser. Performance

Core Web Vitals is the collective name for the three metrics Google defined to measure a page’s real user experience. Performance

What is a country domain (ccTLD)?

ccTLDDEFINITION

A country domain is a two-letter top-level domain extension allocated to a particular country.

On a multilingual site it is one of three address structures: a separate domain for each country. The other two are the subfolder and the subdomain.

It gives the strongest local signal — for a search engine the target country is beyond dispute. But its cost is the highest too: each domain means a separate purchase, a separate renewal, a separate certificate and a separate configuration.

The real price is the division of authority: three separate domains mean building three separate authorities from scratch. Trust accumulated on a single domain spreads to every language, while separate domains cannot share that accumulation.

For small and medium sites the answer is almost always the subfolder. A country domain makes sense only where operations genuinely diverge: a different legal entity, different prices, different legal obligations.

It brings an operational burden too: each domain means a separate certificate, a separate DNS configuration, a separate renewal calendar and separate monitoring. Three domains, three times the management load.

Some country extensions are used generically, and in that case the extension carries no country signal. If such an extension is chosen, the advantage of the local signal disappears and only the cost remains.

The real question when deciding is this: do the markets genuinely diverge — different prices, stock, legal entity, legal obligations? Without those conditions the cost does not repay itself.

Country domain — strongest local signal, highest cost, most scattered authority.
Subdomain — the middle road; the separation is clear but authority can be divided.
Subfolder — authority is shared, maintenance is cheapest. The right answer for most sites.
The deciding test — do the markets genuinely diverge?
Reversal — if this decision is changed later, accumulated indexing is affected.

Examples and exceptions

Turkey’s extension is .tr; businesses mostly use the .com.tr second level. Germany is .de, France .fr. But not every two-letter extension carries a country signal: Google treats a group of them, such as .io, .co, .me and .tv, as generic and does not tie them to a country.

How the target country is determined

On a country domain, the extension itself names the target country. On a generic domain such as .com, that information comes from the region code in hreflang; the old “international targeting” setting in Search Console was removed in 2022.

Common mistakes

Choosing country domains without accounting for split authority — every new domain starts building links from zero.
Buying an extension Google treats as generic (such as .io) expecting a local signal.
Not connecting country domains to each other with hreflang — separate domains must still be declared as one cluster.

Whichever structure is chosen, the language versions are tied together by hreflang; the address structure does not replace that declaration.

We audit a multilingual site’s hreflang cluster and canonicals as part of SEO consulting; if the site has to be built in the target market’s language from the start, our B2B websites service is designed for exactly that.

Multilingual

Crawl budget is the number of requests a search engine allocates to fetching from a site within a given period. Answer engines

Critical rendering path The critical rendering path is the minimum sequence of steps a browser must complete before it can draw a page on screen. Performance

E

Entity An entity means a distinct thing that search and answer engines recognise — a person, an organisation, a place, a product or a concept. Answer engines

F

Field data is the sum of performance measurements experienced by real users on real devices and real networks. Performance

Focus trap A focus trap is when keyboard focus enters a region and cannot leave it again, and WCAG prohibits it explicitly at level A. Accessibility

Font subset A font subset is a font file regenerated with only the characters that are needed. Multilingual

G

GEO (Generative Engine Optimization) is the work of increasing the likelihood that a site is chosen as a source in the answers generated by AI systems. Answer engines

H

hreflang is the markup that declares a page’s different language and region versions to search engines. Multilingual

I

IndexNow is an open protocol that tells search engines immediately that a page has changed. Answer engines

INP (Interaction to Next Paint) is the time from a user interaction until the page responds visually, and Google counts anything under 200 milliseconds as good. Performance

J

JSON-LD (JavaScript Object Notation for Linked Data) is a structured data format that declares a page’s meaning in a machine-readable form without changing the page’s appearance at all. Answer engines

L

Language tag (BCP 47) A language tag is the standard coding form that tells machines which language a text is in. Multilingual

LCP (Largest Contentful Paint) is the paint time of the largest content element in a page’s visible area, and Google counts anything under 2.5 seconds as good. Performance

Live region A live region is an area of a page whose changes a screen reader has to announce to the user. Accessibility

llms.txt is an optional file placed in a website’s root directory that summarises, in Markdown, what the site is about and where its most important pages are for language models. Answer engines

Locale A locale is the setting that defines a user’s language and region together and determines the formatting rules. Multilingual

Localisation (Localization) is adapting content to the culture, habits and search language of a target market; it is a wider undertaking than translation. Multilingual

R

Reflow A reflow is the browser recomputing the positions and sizes of elements on a page after a change. Performance

Relative luminance is the value expressing a colour’s perceived lightness between 0 and 1, and it is the basis of the contrast ratio calculation. Accessibility

S

Screen reader A screen reader is assistive technology that turns on-screen content into speech or braille output and lets the user navigate by keyboard. Accessibility

Semantic HTML means choosing each element for its meaning rather than its appearance — a heading element for a heading, a button element for a button, a list element for a list. Accessibility

Structured data is an additional layer that labels a page’s content with a standard vocabulary machines can understand. Answer engines

T

Text expansion is the same content being of different lengths in different languages, and the layout having to flex accordingly. Multilingual

Translation memory A translation memory is a database that stores previously translated sentences and suggests them when the same or a similar sentence comes up again. Multilingual

TTFB (Time to First Byte) is the time between the browser sending a request and receiving the first byte from the server. Performance

W

WCAG (Web Content Accessibility Guidelines) is the international standard published by the W3C that defines the accessibility of web content through testable success criteria. Accessibility

X

x-default is a special hreflang value declaring the default page to show when no language version matches the user’s language. Multilingual