rib n.

Old English ribb "a rib; one of a series of long, slender, curved bones of humans and animals, forming a kind of cage or partial enclosure for the chief organs," from Proto-Germanic *rebjan (source also of Old Norse rif, Old Saxon ribbi, Old Frisian rib, reb, Middle Dutch, Dutch ribbe, Old High German ribba, German Rippe).

Boutkan finds the old derivation of this from PIE *rebh- "to roof, cover" (on the notion of "a covering" of the cavity of the chest) doubtful, "particularly because the alleged semantic development to 'rib' is found only in Gmc. and Slavic."

Cookery sense of "piece of meat from an ox, pig, etc. containing one or more ribs" is from early 15c. As "a ship's curved frame timber" from 1550s.

Rib-roast "joint of meat for roasting which includes one or more ribs" is by 1889. Rib-eye for a cut of meat that lies along the outer side of a rib is by 1926, American English, with eye in a specialized sense in butchery. Rib joint "brothel" is slang from 1943, probably in reference to Adam's rib (compare rib "woman, wife," attested from 1580s).

"to dupe, tease, fool," by 1930, apparently from rib (n.), which is attested by 1929 in a slang sense of "a joke,"  perhaps a figurative use of poking someone in the ribs (rib-digging "light-heated banter" is attested by 1925).

Earlier it meant "to plow land so as to leave a space between furrows (1735) and "to clean (flax) with a rib" (early 14c.), a special tool for that job, which is probably an extended sense of rib (n.). Compare Middle Low German ribbeisern ("rib-iron"), a tool for cleaning flax. Related: Ribbed; ribbing.