Definition
Search engine optimization (SEO) is the practice of improving content quality, technical structure and backlinks so that pages get indexed and ranked better in the organic (non-paid) results of search engines.
How it works
Search engines decide where pages appear through crawling, indexing and ranking, and SEO addresses each step: publishing content that answers search demand, improving page structure and loading performance, and earning references from other sites. Google’s SEO Starter Guide frames the goal as making a site easy for both users and search engines to understand.
Usage
SEO comes up when planning websites, running content operations or reviewing marketing spend — for example, choosing keywords, tuning page titles and meta descriptions, or analyzing where search traffic changes come from.
Related and confusable terms
SEO targets organic rankings in search engines. Its counterpart is generative engine optimization (GEO), an emerging concept that instead asks whether content gets cited in AI-generated answers.