c.1300 (surname Botouner "button-maker" attested from mid-13c.), from Old French boton "a button," originally "a bud" (12c., Modern French bouton), from bouter, boter "to thrust," common Romanic (cf. Spanish boton, Italian bottone), ultimately from Germanic (see butt (v.)). Thus a button is, etymologically, something that pushes up, or thrusts out.
Meaning "point of the chin" is pugilistic slang, by 1921. A button as something you push to create an effect by closing an (electrical) circuit is attested from 1840s. Button-pusher as "deliberately annoying or provocative person" is attested by 1990 (in reference to Bill Gates, in "InfoWorld" magazine, Nov. 19). In the 1980s it meant "photographer."
late 14c., "to furnish with buttons;" early 15c., "to fasten with buttons" (of a garment,) from button (n.) or from Old French botoner (Modern French boutonner), from boton (n.). Related: Buttoned; buttoning. Button-down (adj.) in reference to shirt collars is from 1916.
button but·ton (bŭt'n)
n.
A knob-like structure, device, or lesion.
To be normal or mentally sound; be sane; be shrewd and aware •Most often in the negative: When I'm sure I no longer have all my buttons I'll quit this line of work/ The old guy doesn't seem to have all his marbles, the way he mumbles to himself
Related Terms[1860+; buttons probably refers to the neatness and completeness of a normal mind compared with the uncertainty and slovenliness of clothes lacking buttons]
7 (also button man or button player or button soldier) A low-ranking member of the Mafia; soldier (1960s+ Underworld)
Related Termsbelly button, chicken switch, hit the panic button, on the button