lappetPronunciation: /ˈlapɪt/Definition of lappet noun 1a fold or hanging piece of flesh in some animals. a loose or overlapping part of a garment. 2 (also lappet moth) a brownish moth, the hairy caterpillars of which have fleshy lappets along each side of the body. Gastropacha quercifolia and other species in the family Lasiocampidae Derivatives lappeted adjective Origin: late Middle English (denoting a lobe of the ear, liver, etc.): diminutive of lap1lappet in other Oxford dictionaries Definition of lappet in the US English dictionary