What is Button?

Button definition and meaning on Dictionary terms:
a small disk, knob, or the like for sewing or otherwise attaching to an article, as of clothing, serving as a fastening when passed through a buttonhole or loop.
anything resembling a button, especially in being small and round, as any of various candies, ornaments, tags, identification badges, reflectors, markers, etc.
a badge or emblem bearing a name, slogan, identifying figure, etc., for wear on the lapel, dress, etc.: campaign buttons.

any small knob or disk pressed to activate an electric circuit, release a spring, or otherwise operate or open a machine, small door, toy, etc.
Botany. a bud or other protuberant part of a plant.
Mycology. a young or undeveloped mushroom. any protuberant part of a fungus.

Zoology. any of various small parts or structures resembling a button, as the rattle at the tip of the tail in a very young rattlesnake.
Boxing Informal. the point of the chin.
Also called turn button. a fastener for a door, window, etc., having two arms and rotating on a pivot that is attached to the frame.
Metallurgy. (in assaying) a small globule or lump of metal at the bottom of a crucible after fusion.
Fencing. the protective, blunting knob fixed to the point of a foil.
Horology. crown(def 19).
Computers. (in a graphical user interface) a small, button-shaped or clearly defined area that the user can click on or touch to choose an option.

verb (used with object)
to fasten with a button or buttons: She quickly buttoned her coat.
to insert (a button) in a buttonhole or loop: He buttoned the top button of his shirt.

to provide (something) with a button or buttons.

verb (used without object)
to be capable of being buttoned: This coat buttons, but that one zips.


reference: https://www.dictionary.com/browse/button