AEO is the discipline of being represented inside the answers these engines generate. ChatGPT, Perplexity, Claude, Gemini, Microsoft Copilot, and Google AI Overviews are all answer engines. They share a common contract-flip with traditional search: ranking on the SERP no longer guarantees the click; being inside the answer is what matters.
AEO glossary
Answer engine
An answer engine is an AI system that synthesises a direct answer to a user query, typically grounded by retrieved sources, instead of returning a ranked list of links.