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."
fem. proper name, Latin, but said to be of Germanic origin and mean literally "laborious" (cognates: Old Norse ama "to trouble"); the name was assimilated with Roman gens name Aemilia.
river in Ireland, the name is said to mean something like "old man river," from a Proto-Celtic word related to Irish sean "old" (from PIE root *sen- "old").