Buttons

a bellboy or page in a hotel.
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) any of the small, labeled areas upon which the user can click with a mouse to choose an option.
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.
to be capable of being buttoned:
This coat buttons, but that one zips.
button up, Informal.

Also, button one’s lip. to become or keep silent.
to fasten securely; close up:
Within a short time, everything on the submarine was buttoned up.
to fasten fully or put on, especially an outer garment:
Button up before going out.
to complete successfully; finish:
The report is all buttoned up.

have all one’s buttons, Informal. to be mentally competent, alert, and sane; have all one’s wits:
At 106 she still has all her buttons.
on the button, Informal. exactly as desired, expected, specified, etc.:
The prediction for snow was right on the button.
Contemporary Examples

How Did We Become Our Parents’ IT? David Frum November 21, 2012
Dallas: A Journal of the Plague City Pete Freedman October 16, 2014
Acid Attacks on Women Spread Terror in Iran IranWire October 17, 2014
The Return of Rev. Wright Michael Tomasky May 16, 2012
Porn’s Behind-the-Camera Feminists Emily Shire February 25, 2014

Historical Examples

The Twelfth Hour Ada Leverson
Diggers in the Earth Eva March Tappan
Famous Adventures And Prison Escapes of the Civil War Various
The Pirate’s Pocket Book Dion Clayton Calthrop
The Letters of her Mother to Elizabeth W. R. H. (William Rutherford Hayes) Trowbridge

noun
(functioning as sing) (Brit, informal) a page boy
noun
a disc or knob of plastic, wood, etc, attached to a garment, etc, usually for fastening two surfaces together by passing it through a buttonhole or loop
a small round object, such as any of various sweets, decorations, or badges
a small disc that completes an electric circuit when pushed, as one that operates a doorbell or machine
a symbolic representation of a button on the screen of a computer that is notionally depressed by manipulating the mouse to initiate an action
(biology) any rounded knoblike part or organ, such as an unripe mushroom
(fencing) the protective knob fixed to the point of a foil
a small amount of metal, usually lead, with which gold or silver is fused, thus concentrating it during assaying
the piece of a weld that pulls out during the destructive testing of spot welds
(rowing) a projection around the loom of an oar that prevents it slipping through the rowlock
(Brit) an object of no value (esp in the phrase not worth a button)
(slang) intellect; mental capacity (in such phrases as a button short, to have all one’s buttons, etc)
(informal) on the button, exactly; precisely
verb
to fasten with a button or buttons
(transitive) to provide with buttons
(transitive) (fencing) to hit (an opponent) with the button of one’s foil
button one’s lip, button up one’s lip, button one’s mouth, button up one’s mouth, to stop talking: often imperative
n.
v.

The chin; point of the chin: I got clipped square on the button (1920+)
The clitoris; clit (1870s+)
A small quantity of a narcotic: There exists some traffic, however, in ”buttons,” or small amounts (1960s+ Narcotics)
The rounded top of the peyote plant (1960s+ Narcotics)
A police officer’s badge; potsy, tin (1920s+)
(also buttons) A police officer •Blue and buttons was used of the police (1900+)

button one’s lip
button up