Nipple
A nipple is a structure from which a fluid emanates. In biological terms, it is the section of the body through which nourishment is transferred from parent to infant.

In 2151, Commander Tucker was accidentally impregnated by a female Xyrillian without his knowledge. The first indication of the pregnancy was the appearance of a growth on his wrist. This growth turned out to be a nipple. ()

Female Klingons had nipple on their breasts. ()

See also 
 Breast
 Breast feeding

External link
 
Anatomy