“A compact statement, such as a maxim or proverb, that concisely expresses a principle or common experience. The term was first used by Hippocrates. The beginning sentence of his Aphorisms is a well-known example: ‘Life is short, art is long, opportunity fleeting, experimenting dangerous, reasoning difficult.”
Murphy, Bruce, ed. Benet’s Reader’s Encyclopedia, Fourth Edition. New York: Harper Collins, 1996.