noun.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

• campaign button
• has his finger on the button

noun.a usually circular metal or plastic badge bearing a stamped design or printed slogan

• knows how to push my buttons

noun.something that resembles a button: such as

verb.to furnish or decorate with buttons

• I told you to button your lip.
• This dress buttons at the back.

verb.to pass (a button) through a buttonhole or loop

verb.to close or fasten with buttons —often used with up