Generative Engine Optimization is the discipline of making a website legible to ChatGPT, Claude, Perplexity, Google AI Overviews, and other retrieval-augmented assistants. Unlike classic SEO, the goal is not a ranked blue link — it is being used as a citation inside a generated answer.
GEO overlaps with SEO in about 30 percent of its surface area (crawlability, canonical URLs, JSON-LD). The rest is new: llms.txt, answer-ready content blocks, E-E-A-T signals that models trust, and machine-readable product feeds. A Shopify store can score perfectly on Lighthouse and still be invisible to an AI retriever.
The practical test: ask ChatGPT a buyer-intent question about your category, and see whether your brand is cited. If it isn't, GEO is your gap.
Typing "best moissanite rings for proposals" into ChatGPT returns 3 brand citations — GEO is the practice of becoming one of those 3.