SEO glossary
Short definitions of the SEO terms you actually use — for quick answers in briefs and stand-ups.
Canonical URL
A canonical URL is the "primary" version of a page you tell search engines about via `<link rel="canonical">` to prevent duplicate-content indexation.
CLS — Cumulative Layout Shift
CLS — how much the layout "jumps" during load. Target: ≤ 0.1.
Core Web Vitals
Core Web Vitals are Google's three user-experience metrics: LCP (loading speed), INP (responsiveness) and CLS (visual stability).
hreflang
hreflang is the attribute multilingual sites use to tell search engines that a page has language alternates.
INP — Interaction to Next Paint
INP — the time from a user interaction (click, tap) to the rendered result. Replaced FID in March 2024. Target: ≤ 200ms.
LCP — Largest Contentful Paint
LCP — the time until the largest visible element finishes rendering. Target: ≤ 2.5 seconds at the 75th percentile.
noindex
noindex is the directive that bars search engines from indexing a page. Set via meta tag or X-Robots-Tag header.
robots.txt
robots.txt is a plain-text file in the site root that tells search bots which sections to crawl or skip.
sitemap.xml
sitemap.xml is an XML file listing all your important URLs that you submit to search engines to speed up and clarify indexing.
Yandex IX (ICS)
IX (Site Quality Index, sometimes ICS) — Yandex's public 0-to-∞ metric reflecting the site's usefulness in Yandex's view.