1 : a. a small knob or disk secured to an article (as of clothing) and used as a fastener by passing it through a buttonhole or loop.
b. a usually circular metal or plastic badge bearing a stamped design or printed slogan.
2 : something that resembles a button: such as
a.any of various parts or growths of a plant or of an animal: such as
b. BUD
: an immature whole mushroom
especially : BUTTON MUSHROOM
3 : the terminal segment of a rattlesnake’s rattle
a . a small globule of metal remaining after fusion (as in assaying)
b . a guard on the tip of a fencing foil
4 : a: PUSH BUTTON
b: something (such as a push button) that has the real or symbolic capability of initiating a catastrophe (such as a nuclear attack) has his finger on the button
c: a hidden sensitivity that can be manipulated to produce a desired response knows how to push my buttons
d: a usually box-shaped computer icon that initiates a specific software function
5 : the point of the chin especially as a target for a knockout blow