An AI citation is a source that an AI engine links to or names to support its answer.
Assistants that search the web, such as ChatGPT search or Perplexity, often show the pages they drew on. Being cited sends visitors and signals that the engine trusts the page; being named in the answer without a citation still shapes what the shopper buys.
The pages cited for a question are often not the brand's own: reviews, comparison articles and forums are common. That's why mentions on other sites matter.