Old English ribb "rib," from Proto-Germanic *rebja- (cf. Old Norse rif, Old Saxon ribbi, Old Frisian ribb, Middle Dutch, Dutch ribbe, Old High German ribba, German Rippe), literally "a covering" (of the cavity of the chest), from PIE *rebh- "to roof, cover" (cf. Greek ereptein "to roof," Old Church Slavonic rebro "rib, reef"). As an item of food from early 15c. Rib joint "brothel" is slang from 1943, probably in reference to Adam's rib (cf. rib "woman, wife," attested from 1580s).