button · noun C /ˈbʌt.ən/Full view
button (ON MACHINE)
B1 a switch that you press to control a piece of equipment
Dictionary example:

He inserted the DVD and pressed the 'play' button.

Learner example:

I could have written a letter in a bottle but waiting for the answer would take a decade, now [with email] it's just a click of a button. (Preliminary English Test; B1; Arabic)

button (ON CLOTHING)
B1 a small, round object used to fasten something, for example a shirt or coat
Dictionary example:

I did up/undid the buttons on my blouse.

Learner example:

It was a long dress with some square buttons [on the] front of it. (Preliminary English Test; B1; Italian)

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