1.nounA wager, an agreement between two parties that a stake (usually money) will be paid by the loser to the winner (the winner being the one who correctly forecast the outcome of an event).
"Dylan owes Fletcher $30 from an unsuccessful bet."
2.nounA degree of certainty.
"It’s a safe bet that it will rain tomorrow."
3.verbTo stake or pledge upon the outcome of an event; to wager.
4.verbTo be sure of something; to be able to count on something.
"Fancy going for a drink after work?
You bet I do!"
5.verbTo place money into the pot in order to require others do the same, usually only used for the first person to place money in the pot on each round.