† unisoundObs.rare. [Alteration of unison n.: see uni- and sound n.3] A unison. 1763Ann.Reg., Misc. 192/2 By dividing the musical notes into six, as nature directs, the unisound will fall on the seventh note.Ibid. 193/1 [The notes]i, j, s, d, are likewise unisounds to f, z, t, alike.