Performance note: Build on Janet Levy’s work on the signification of unisons, and that of Armin Raab on their structural functions in Haydn’s quartets to examine how unisons convey meanings in these works. Argue that one of the most salient characteristics of the unison in the quartets is its capacity for both syntactic and semantic ambiguity. The unison is a peculiar feature in a genre especially valued for its complex “conversational” textures.