Definition
A citation is a source reference inside an AI answer that resolves to a specific URL. It is not the same as a retrieval candidate: an assistant typically retrieves a dozen or more pages and cites only a few of them in the text it writes.
Why it matters
Counting the retrieval pool instead of the marked citations inflates citation numbers several times over. It is the single most common way AI visibility reports overstate reach.
How to measure it
Parse the bracketed markers in the answer text and map each one back to a real URL; discard markers that do not resolve. Report citations and distinct cited domains separately, because one answer citing twelve of your pages is not twelve times the reach.