nubbin

Etymology
Perhaps.

Noun

 * 1) A stub, especially a stub of undeveloped corn or fruit or nipple.
 * 2)  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.
 * As an avid button collector, I have had to develop an efficient way of removing the nubbin of thread from the buttonhole.
 * As an avid button collector, I have had to develop an efficient way of removing the nubbin of thread from the buttonhole.