Meaning of "button" in Essential American English Dictionary

button

noun us /ˈbʌt·ən/

B1 a small, round object that you push through a hole to fasten clothes:

There are buttons down the front of her jacket.

B1 a switch that you press to control a piece of equipment:

Press the play button to listen to your recording.

(Definition of “button” from the Webster's Essential Mini Dictionary © Cambridge University Press)