An answer engine is a system that responds to a query with a direct, synthesized answer instead of a list of links — Perplexity, ChatGPT with browsing, and Google's AI Overviews are the canonical examples.
Search engines rank documents and let the user synthesize; answer engines synthesize first and cite documents second. The shift compresses the funnel: the consideration set that used to be ten blue links is now three named brands in a paragraph.
For brands, the strategic difference is winner-take-most. Rank #4 on a search page still gets clicks; brand #4 in an AI answer frequently does not exist — the answer only named three.