2. The orifice at which any animal liquid, as the oil from an
oil bag, is discharged. [R.] --Derham.
3. Any small projection or article in which there is an
orifice for discharging a fluid, or for other purposes;
as, the nipple of a nursing bottle; the nipple of a
percussion lock, or that part on which the cap is put and
through which the fire passes to the charge.
4. (Mech.) A pipe fitting, consisting of a short piece of
pipe, usually provided with a screw thread at each end,
for connecting two other fittings.
{Solder nipple}, a short pipe, usually of brass, one end of
which is tapered and adapted for attachment to the end of
a lead pipe by soldering.