 One long-standing issue about ambiguity is that it assumes a difference between something like sense and reference. While some words can clearly be used to refer to things that are wildly different in ontic category, that has not been taken to be sufficient for a claim to ambiguity. In theory, a phrase could be ambiguous and yet differ not at all in reference: imagine a term t that was ambiguous between two meanings, but it turned out as highly surprising essential condition that things that were t in the first sense were also t in the second sense – while this seems unlikely to happen, it is by no means conceptually impossible.