nipple (n.)
1530s, nyppell, "teat, duct-laden extremity of a mammalian breast," alteration of neble (1520s), probably diminutive of neb "bill, beak, snout" (see neb), hence, literally "a small projection." In reference to an artificial device on an infant's bottle, from 1875. A 16c.-17c. slang term for a woman's nipples was cherrilets.