nubbin

noun3

1. •
   A stub, especially a stub of undeveloped corn or fruit or nipple.
2. •
   (informal) A small protuberance, bud, bump, or knob.

   • As an avid button collector, I have had to develop an efficient way of removing the nubbin of thread from the buttonhole.
3. •
   (slang, vulgar) Synonym of clitoris.