SEO Glossary
A comprehensive A-Z reference guide to SEO terminology. Master the vocabulary of search engine optimization.
What Is Domain Rating (DR)? Definition & How to Improve It
Domain Rating (DR) is Ahrefs' proprietary score (0–100) measuring a website's backlink profile strength. Learn how DR is calculated and proven tactics to raise your score.
What Are Backlinks? SEO Definition, Types & How to Earn Them
Backlinks are inbound links from other websites to yours — a top Google ranking factor. Learn the difference between dofollow and nofollow links and how to earn high-quality backlinks.
What Is Crawl Budget? SEO Definition & Optimization Guide
Crawl budget is the number of pages Googlebot crawls on your site per day. Learn what controls it, why it matters for large sites, and how to optimize it so your most important pages get indexed first.
What Is Schema Markup? SEO Definition, Types & Implementation
Schema markup is JSON-LD structured data that helps Google understand your content and display rich results (stars, FAQs, how-tos) in SERPs. Learn the most valuable schema types for SEO.
What Is Alt Text? SEO & Accessibility Definition with Examples
Alt text is an HTML image attribute that describes visuals for search engines and screen readers. Learn how to write descriptive, keyword-rich alt text that improves image SEO and accessibility.