n. & v.
n. 1 a small disc or knob sewn on to a garment, either to fasten it by being pushed through a buttonhole, or as an ornament or badge. 2 a knob on a piece of esp. electronic equipment which is pressed to operate it. 3 a a small round object (chocolate buttons). b (attrib.) anything resembling a button (button nose). 4 a a bud. b a button mushroom. 5 Fencing a terminal knob on a foil making it harmless.
v. 1 tr. & intr. = button up 1. 2 tr. supply with buttons. buttonball tree (or button wood) US a plane-tree, Platanus occidentalis. button chrysanthemum a variety of chrysanthemum with small spherical flowers. buttoned up colloq. 1 formal and inhibited in manner. 2 silent. button one's lip esp. US sl. remain silent. button mushroom a young unopened mushroom. button-through (of a dress) fastened with buttons from neck to hem like a coat. button up 1 fasten with buttons. 2 colloq. complete (a task etc.) satisfactorily. 3 colloq. become silent. not worth a button worthless. on the button esp. US sl. precisely. buttoned adj. buttonless adj. buttony adj.
[ ME f. OF bouton, ult. f. Gmc ]