BET

[noun] [C]A bet is an amount of money which you risk on the unknown result of an event, such as a horse race.He placed/put a bet on the horse which was the favourite to win.(informal) A bet is also a guess or opinion.My bet is their baby will be a girl. [+ (that) clause]If you do something for/(US usually) on a bet, you do it because someone says that you cannot or will not do it.She jumped in the fountain for a bet.Putting your savings in a high-interest account is a good bet/your best bet (= the wisest thing to do).It is a fair bet (= It is quite likely) that the government will not act on any of the recommendations in the report. [+ (that) clause]It's a safe bet (= It is very likely) that he won't remember my birthday tomorrow. [+ (that) clause]If you make a bet with someone about something, you both have different opinions about whether it is true or will happen.She made a bet with her brother about whether their mother would notice the broken vase.