1520s, "a tax of one-fifth," from Middle French quint, from Latin quintus "the fifth," ordinal to quinque "five" (from PIE root *penkwe- "five"). Used in English of various groups of five since 17c. First attested 1935 as a shortening of quintuplet (American English; British English prefers quin); used originally of the Dionne quintuplets, born May 28, 1934, near Callander, Ontario, Canada.
