n.
Pronunciation: ' käs-t ə
Function: noun
Inflected Form: plural cos · tae \ -( ˌ )t ē , - ˌ t ī \
Etymology: Latin ― more at COAST
Date: circa 1771
1 : 1 RIB 1A
2 : a part (as the midrib of a leaf or the anterior vein of an insect wing) that resembles a rib
– cos · tal \ -t ə l \ adjective