Brief
Middle English: from Old French brief, from Latin brevis ‘short’. The noun is via late Latin breve ‘note, dispatch’, hence ‘an official letter’.
wiktionary
From Middle English breef, breve, bref, from Old French brief, bref, from Latin brevis(“short”), from Proto-Indo-European *mréǵʰus(“short, brief”). Doublet of merry.
etymonline
brief (adj.)
c. 1300, bref, "of short duration;" early 14c., "small with respect to length, short;" from Latin brevis (adj.) "short, low, little, shallow," from PIE *mregh-wi-, from root *mregh-u- "short."
brief (n.)
early 14c., bref, "a writing issued by authority," from Latin breve (genitive brevis), noun derivative of adjective brevis "short, little" (from PIE root *mregh-u- "short") which came to mean "letter, summary," specifically a letter of the pope (less ample and solemn than a bull), and thus came to mean "letter of authority," which yielded the modern, legal sense of "systematic summary of the facts of a case" (1630s). Sense of "a short or concise writing" is from 1560s. In German, Brief has become the general word for "an epistle or letter."
brief (v.)
"to give instructions or information to," 1866; originally "to instruct by a brief" (1862), from brief (n.). Related: Briefed; briefing.
