Risk something, usually a sum of money, against someone else's on the basis of the outcome of a future event, such as the result of a race or game.
He made a bet that he could give up smoking in three weeks.
His bet on the roulette table turned out to be a lucky one, and he walked away with a substantial prize.
The friendly bet between colleagues over who could finish a challenging task first added some excitement to the workday.
Placing a bet on the outcome of a sports event can make watching the game even more thrilling for fans.
