[but.ton] n, often attrib [ME boton, fr. MF, fr. OF, fr. boter to thrust--more at butt] (14c) 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 usu. circular metal or plastic badge bearing a stamped design or printed slogan "campaign ~"
2: something that resembles a button: as a: any of various parts or growths of a plant or of an animal: as (1): an immature whole mushroom (2): the terminal segment of a rattlesnake's rattle b: a small globule of metal remaining after fusion (as in assaying) c: a guard on the tip of a fencing foil
3: push button
4: the point of the chin esp. as a target for a knockout blow -- but.ton.less adj -- on the button : exactly "arrived at noon on the button"; also: exactly on target: on the nose "the estimate was right on the button"
button vb but.toned ; but.ton.ing vt (14c) 1: to furnish or decorate with buttons
2. a: to pass (a button) through a buttonhole or loop b: to close or fasten with buttons--often used with up "~ up your overcoat" 3 a: to close (the lips) to prevent speech "~ your lip" b: to close or seal tightly--usu. used with up "~ up the house for winter" ~ vi: to have buttons for fastening "this dress ~s at the back" -- but.ton.er n