teat

[teet, tit] /tit, tɪt/
noun
1.
the protuberance on the breast or udder in female mammals, except the monotremes, through which the milk ducts discharge; nipple or mammilla.
2.
something resembling a teat.
Origin
1250-1300; Middle English tete < Old French < Germanic; see tit2
British Dictionary definitions for teat

teat

/tiːt/
noun
1.
  1. the nipple of a mammary gland
  2. (in cows, etc) any of the projections from the udder through which milk is discharged See nipple
2.
something resembling a teat in shape or function, such as the rubber mouthpiece of a feeding bottle
Word Origin
C13: from Old French tete, of Germanic origin; compare Old English titt, Middle High German zitze
Word Origin and History for teat
n.

mid-13c., from Old French tete "teat" (12c.), from Proto-Germanic *titta (source of Old English titt, see tit).

teat in Medicine

teat (tēt, tĭt)
n.

  1. See nipple.

  2. The female breast; mamma.

  3. A papilla.

teat in Science
teat
  (tēt, tĭt)   
A small projection near the center of the mammary gland of many female mammals that contains the outlet of the milk ducts. Each teat contains a single milk duct, while nipples each contain more than one.