What are GEO, AEO, AIO, HEO and SEO?

They are five names for overlapping layers of search and AI visibility work. SEO (Search Engine Optimization) earns ranked link positions on search results pages. GEO (Generative Engine Optimization) structures content, schema, and entity signals so generative AI systems cite a brand inside a synthesized answer. AEO (Answer Engine Optimization) is the narrower subset of GEO focused on being selected as the single direct answer to a question, using concise answer blocks and structured markup. AIO (AI Optimization) is the broadest layer: a brand's entity definition and citation surface across every AI system that ingests information about it. HEO (Hybrid Engine Optimization) runs SEO and GEO as one strategy for brands that need both rankings and AI citations. SEO targets crawlers and ranking algorithms; GEO and AEO target retrievers and language-model source selection.