button

US /ˈbʌt̬.ən/
UK /ˈbʌt̬.ən/
"button" picture
1.

a small knob or disc sewn onto a garment, serving as a fastener by passing through a buttonhole

:
She sewed a new button on her coat.
This shirt has too many buttons.
2.

a small, usually round, control that you push to operate a device or machine

:
Press the red button to start the machine.
The remote control has many small buttons.
1.

fasten (a garment) with buttons

:
Please button up your coat, it's cold outside.
He quickly buttoned his shirt before leaving.
2.

press a button on a device or machine

:
Just button the remote to change the channel.
He buttoned the elevator to the tenth floor.