mid-15c., "to lift or throw with a sudden movement," of uncertain origin, possibly from a Scandinavian source (compare dialectal Norwegian tossa "to strew, spread"). Food preparation sense (with reference to salad, etc.) is recorded from 1723. Intransitive sense "be restless; throw oneself about" is from 1550s. Related: Tossed; tossing.
"an act of throwing," 1630s, from toss (v.). Meaning "a coin toss" is from 1798.