   in its most general form, a nipple is a structure from which a fluid emanates. more specifically, it is the projection on the breasts or udder of a mammal by which breast milk is delivered to a mother's young. in this sense, it is often called a teat, especially when referring to non-humans, and the medical term used to refer to it is papilla. the rubber mouthpiece of a baby bottle or pacifier may also be referred to as a "nipple" or a "teat". in many cultures, female nipples are considered an erogenous zone and in some it is considered a public indecency to uncover them in public. ==etymology== the word "nipple" most likely originates as a diminutive of neb, an old english word meaning "beak", "nose", or "face", and which is of germanic origin. the words "teat" and "tit" share a germanic ancestor. the second of the two, tit, was inherited directly from proto-germanic, while the first entered english via old french. ==anatomy==  in the anatomy of mammals, a nipple, mammary papilla or teat is a small projection of skin containing the outlets for 15â20 lactiferous ducts arranged cylindrically around the tip. the skin of the nipple is rich in a supply of special nerves that are se
Breast_anatomy Exocrine_system Glands Mammal_anatomy Secondary_sexual_characteristics