Definition
A citation is a source reference inside an AI answer: the link, footnote or source card that ChatGPT, Gemini, Perplexity or Google's AI Overviews show to indicate which web page a claim is based on. Where a classic search engine lists ten blue links, an answer engine writes a single answer and points to a handful of pages within it. Those references are the citations.
The term comes from academia, where being cited means your work is used as a source by others. AI search works in a similar way: while generating an answer, the engine retrieves pages, selects the passages that best support the question, and displays those pages as sources. A citation is therefore not a ranking in the classic sense, but proof that your page was actually used to build the answer.
There is an important difference between a citation and a brand mention. With a mention, the model names your brand in the text without a link. With a citation, there is a clickable reference to a specific URL. Both are valuable, but a citation also drives traffic and is easier to measure. In Perplexity and ChatGPT search, citations appear as numbered sources; in AI Overviews and AI Mode they show up as cards beside or below the answer.
Which pages get cited depends on three things: whether the engine can fetch your page (crawlability and speed), whether the page contains a concrete, self-contained answer that can be quoted, and whether the model judges the source to be trustworthy. Pages with a direct answer in the first paragraph, clear entities, sourced numbers and a recognisable author are chosen more often than long introductions without a position.
Citations are measurable. Because AI answers vary from run to run, you measure them by asking the same set of prompts repeatedly and counting how often your domain appears as a source, per engine and per topic. Traze does this automatically and ties the result back to the page that earned the citation, so you can see which content is working.