Entomology. a strong spine or group of bristles on the hind wing of many butterflies and moths, projecting beneath the forewing and serving to hold the two wings together in flight.
Main Entry: fren·u·lum Pronunciation: 'fren-y&-l&m Function: noun Inflected Form: pluralfren·u·la/-l&/ : a connecting fold of membrane serving to support or restrain a part (as the tongue)