SEO & Web Performance Glossary
Definitions and explanations of key SEO and web performance terms.
A
ARIA (Accessible Rich Internet Applications)
A set of HTML attributes that enhance accessibility for dynamic content and custom UI components.
AVIF
A next-generation image format offering better compression than WebP, based on the AV1 video codec.
Above the Fold
The portion of a webpage that is visible without scrolling, critical for first impressions and LCP optimization.
Alt Text (Alternative Text)
A description of an image that provides context for screen readers and search engines.
Anchor Text
The clickable text in a hyperlink that provides context about the linked page's content.
B
Backlink
A link from another website pointing to your site, serving as a vote of confidence and ranking signal.
Bounce Rate
The percentage of visitors who leave a site after viewing only one page without further interaction.
Browser Caching
Storing static resources locally in the browser to avoid re-downloading them on subsequent visits.
C
CDN (Content Delivery Network)
A geographically distributed network of servers that delivers web content to users from the nearest location.
CLS (Cumulative Layout Shift)
A Core Web Vital metric measuring visual stability by quantifying unexpected layout shifts. Good CLS is under 0.1.
CSR (Client-Side Rendering)
A technique where JavaScript renders content in the browser after the initial HTML shell loads.
Canonical URL
The preferred URL for a page when multiple URLs could serve the same or similar content.
Code Splitting
A technique that breaks JavaScript bundles into smaller chunks loaded on demand, reducing initial load time.
Compression (Gzip/Brotli)
Server-side compression algorithms that reduce file transfer sizes, speeding up content delivery.
Core Algorithm Update
Significant changes Google makes to its search ranking algorithm that can broadly affect search results across many sites and industries.
Core Web Vitals
A set of three specific metrics (LCP, CLS, INP) that Google considers essential for user experience and uses as ranking signals.
CrUX (Chrome User Experience Report)
Google's public dataset of real user experience data collected from Chrome users who have opted in.
Crawl Budget
The number of pages Googlebot will crawl on your site within a given timeframe.
Crawl Depth
The number of clicks required to reach a page from the homepage, affecting how easily search engines discover and prioritize content.
Crawling
The process by which search engine bots discover and fetch web pages by following links.