n. 1 a small projection in which the mammary ducts of either sex of mammals terminate and from which in females milk is secreted for the young. 2 the teat of a feeding-bottle. 3 a device like a nipple in function, e.g. the tip of a grease-gun. 4 a nipple-like protuberance. 5 US a short section of pipe with a screw-thread at each end for coupling.
[ 16th c., also neble, nible, perh. dimin. f. neb ]