A grounding source the model surfaces to the reader as a reference: a subset of what it retrieved, and an attribution of a source rather than a mention of your brand.
A citation is a grounding source the model surfaces to the reader as a reference: the numbered link, an entry in a "sources" list, or the attribution attached to a claim. Every citation was first a grounding source, though most grounding sources are never cited. The model retrieves far more than it points at, and the citation is the small subset it chose to show.
A citation attributes a source. It says the claim rests on a given page. It does not say your brand appeared in the readable text of the answer, which is a separate event called a mention. The two come apart often: a page can be cited as evidence while a competitor is the brand recommended in the sentence. Natzir Turrado's line holds the distinction well: citations are the bibliography, not the brainstorm.
A citation is a retrieval-side outcome, so it responds to content and relevance in a way that a mention, driven by the model's prior, does not. That gap makes citation a measurement trap. A tracker that reports "cited as a grounding source" as though it meant "cited in the answer" is counting a different layer of the pipeline from the one that carries commercial weight.
Full article: Grounding Source ≠ Citation ≠ Mention.
