Answer engine optimisation, or AEO, is the work of structuring content so that a search or AI system picks it as the answer to a question, rather than one of ten possible answers. It covers Google featured snippets, AI Overviews, People Also Ask, and the spoken replies given by Siri, Alexa and Google Assistant.
The distinction from ordinary SEO is narrow but decisive. Ranking puts you in a list the reader still has to choose from. An answer removes the list. On a phone or a smart speaker there is frequently no second result at all, so the gap between first and second place is the gap between the whole enquiry and none of it.
What wins an answer is mostly format rather than authority. The systems look for a direct response, close to the question, written in a shape they can lift: a short paragraph for a definition, an ordered list for a process, a table for a comparison. A page that buries its answer under an introduction loses to a weaker page that leads with it.
There is a second, newer reason to care. AI Overviews and assistants draw on the same answer-shaped passages, so AEO work tends to pay twice. If you want the broader AI search programme around it, that is covered on our AI SEO page; if you want to be a source inside longer generated answers, see GEO.