Noah Webster
Bet
BET, noun A wager; that which is laid, staked or pledges in a contest, to be won, either by the victorious party himself, or by another person, in consequence of his victory. At a race, a man lays a bet on his own horse, or on the horse of another man.
BET, verb transitive To lay a bet; to lay a wager; to stake or pledge something upon the event of a context.
BET, the old participle of beat, is obsolete or vulgar.