xy的回答：

nipple n.（名词） 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. 乳头：靠近乳腺中心的小的凸起物，含有乳导管的出口，幼小的哺乳动物从成年雌性身上由此吸取乳汁；乳头 The rubber cap on a bottle from which a baby nurses. 橡皮乳头：奶瓶上用于喂婴儿用的橡皮奶头 A pacifier for an infant. 婴儿用的奶嘴 Any of various devices functioning like or resembling a nipple, especially: 似乳头的东西：任何一种具有类似乳头功能的器具或设备，尤指： A regulated opening for discharging a liquid, as in a small stopcock. 水龙头：用于控制液体排出的开口，如在小的旋塞阀里 A pipe coupling threaded on both ends. 螺纹接头：一种两端都带外螺纹的管子 A short extension of pipe to which a nozzle can be attached. 用于绑缚喷嘴的一节伸出的短管 A small projection through which grease in a grease gun can be forced into a bearing. 滑油嘴：一个小的突起，通过它滑油枪中的润滑油能被注入轴承 A natural or geographic projection resembling a nipple, as a mountain crest. 乳头状物：类似乳头的任何自然的或地理上的突起物，如山顶

xy的回答：

nipple n.（名词） 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. 乳头：靠近乳腺中心的小的凸起物，含有乳导管的出口，幼小的哺乳动物从成年雌性身上由此吸取乳汁；乳头 The rubber cap on a bottle from which a baby nurses. 橡皮乳头：奶瓶上用于喂婴儿用的橡皮奶头 A pacifier for an infant. 婴儿用的奶嘴 Any of various devices functioning like or resembling a nipple, especially: 似乳头的东西：任何一种具有类似乳头功能的器具或设备，尤指： A regulated opening for discharging a liquid, as in a small stopcock. 水龙头：用于控制液体排出的开口，如在小的旋塞阀里 A pipe coupling threaded on both ends. 螺纹接头：一种两端都带外螺纹的管子 A short extension of pipe to which a nozzle can be attached. 用于绑缚喷嘴的一节伸出的短管 A small projection through which grease in a grease gun can be forced into a bearing. 滑油嘴：一个小的突起，通过它滑油枪中的润滑油能被注入轴承 A natural or geographic projection resembling a nipple, as a mountain crest. 乳头状物：类似乳头的任何自然的或地理上的突起物，如山顶

δΗυαηの的回答：

n. 乳头, 奶嘴

poring的回答：

乳头