n.
Pronunciation: ' ə n-d ə r- ˌ wi ŋ
Function: noun
Date: 1535
1 : one of the posterior wings of an insect
2 : any of various noctuid moths (esp. genus Catocala ) that have the hind wings banded with contrasting colors (as red and black) ― called also underwing moth
3 : the underside of a bird's wing