A third Nipple

In England, a nubbin is a clitoris.
Sometimes referred to as pleasure nubbin.

Nub is a slang term for a woman's clit. Nubbin' is the act of going down on a woman and...Well...You get the picture...

A third nipple on the chest of someone

A third nipple or boob.

It’s a small lump that shows that u have lost a limb. You will never be able to live a normal life again.