Definition of "brevity"

Thanks to Global Positioning Systems we can see that Europe and North America are parting at about the speed a fingernail grows—roughly two yards in a human lifetime. If you were prepared to wait long enough, you could ride from Los Angeles all the way up to San Francisco. It is only the brevity of lifetimes that keeps us from appreciating the changes.

2005, Bill Bryson, A short history of nearly everything

[B]revity is the soul of wit,And tediousness the limbs and outward flourishes[.]

c. 1599–1602 (date written), William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene ii]

Whenever a public question comes to such a crisis that the opportunities for individual intervention are reduced to the smallest possible compass, Mr. Roebuck is sure to step in with a formula, summing up the case with indignant brevity, censuring somebody, or panegyrizing somebody.

1856 June 14, “Head and Tail”, in The Saturday Review of Politics, Literature, Science, and Art, volume 2, number 33, London: John W. Parker and Son, page 142

A good technical writing style will now be defined as a style possessing clarity, brevity, and variety.

1966, Jackson E. Morris, Principles of scientific and technical writing