1
- the small projection of a woman's or girl's breast in which the mammary ducts terminate and from which milk can be secreted（女性的）乳头, 奶头。
1.1
- the corresponding vestigial structure in a male（男性的）乳头。
1.2
- the teat of a female animal（雌性动物的）奶头。
1.3
- N. Amer. the teat of a feeding bottle〈北美〉（奶瓶的）奶嘴。
2
- a small projection on a device or machine, especially one from which oil, grease, or other fluid is dispensed in small amounts油嘴; 喷嘴。
2.1
- a short section of pipe with a screw thread at each end for coupling螺纹接套。
with obj.(一般作be nippled)
- provide (something) with a projection like a nipple提供乳头状隆起物：
rocks nippled with limpets.
附着着帽贝的岩石。
词源
mid 16th cent. （also as neble, nible）： perhaps a diminutive of NEB.