bæk.tɔːk bæk.tɔk lɪp maʊθ sæs either the outer margin or the inner margin of the aperture of a gastropod's shell the top edge of a vessel or other container either of two fleshy folds of tissue that surround the mouth and play a role in speaking an impudent or insolent rejoinder don't give me any of your sass (botany) either of the two parts of a bilabiate corolla or calyx