nipple

[nip-uh l] /ˈnɪp əl/
noun
1.
a protuberance of the mamma or breast where, in the female, the milk ducts discharge; teat.
2.
something resembling it, as the mouthpiece of a nursing bottle or pacifier.
3.
a short piece of pipe with threads on each end, used for joining valves.
Origin
1520-30; earlier neble, nib(b)le, nepil; perhaps akin to nib; compare Danish nip point; see -le
Related forms
nippleless, adjective
British Dictionary definitions for nipple

nipple

/ˈnɪpəl/
noun
1.
Also called mamilla, papilla, teat. the small conical projection in the centre of the areola of each breast, which in women contains the outlet of the milk ducts related adjective mamillary
2.
something resembling a nipple in shape or function
3.
Also called grease nipple. a small drilled bush, usually screwed into a bearing, through which grease is introduced
4.
(US & Canadian) an informal word for dummy (sense 11)
Word Origin
C16: from earlier neble, nible, perhaps from neb, nib
Word Origin and History for 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.

nipple in Medicine

nipple nip·ple (nĭp'əl)
n.
The projection at the apex of the mammary gland, on the surface of which the lactiferous ducts open, surrounded by the circular pigmented areola. Also called mamilla, papilla mammae, teat, thelium.

nipple in Science
nipple
  (nĭp'əl)   
A small projection near the center of the mammary gland. In females, the nipple contains the outlets of the milk ducts.
nipple in Technology