The protuberance through which milk is drawn from the breast or mamma; the mammilla; a teat; a pap.
- The small projection near the center of the mammary gland containing the outlets of the milk ducts through which young mammals obtain milk from the adult female; a teat.
- A corresponding projection of the male breast.
- The rubber cap on a bottle from which a baby nurses.
- A pacifier for an infant.
- Any of various devices functioning like or resembling a nipple, especially:
- A regulated opening for discharging a liquid, as in a small stopcock.
- A pipe coupling threaded on both ends.
- A short extension of pipe to which a nozzle can be attached.
- A small projection through which grease in a grease gun can be forced into a bearing.
- A natural or geographic projection resembling a nipple, as a mountain crest.