sweep·stake / ˈswēpˌstāk/ • n. (also sweepstakes) a form of gambling, esp. on horse races, in which all the stakes are divided among the winners: [as adj.] a sweepstake ticket. ∎  a race on which money is bet in this way. ∎  a prize or prizes won in a sweepstake.

sweepstake a form of gambling, especially on horse races, in which all the stakes are divided among the winners; the word originally (from the late 14th century) meant someone who ‘sweeps’, or takes the whole of, stakes in a game; in figurative usage, someone who took or appropriated everything. From the 15th to the 17th century, Sweepstake was often used as a ship's name.

From the late 18th century, the word meant a prize won in a race or contest in which the whole of the stakes contributed by the competitors were taken by the winner or a limited number of them; the current meaning developed from this.