n A 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).
v To agree that payment be made to the successful forecaster of the result of an event (usually sporting) by the other party in the agreement. To make a guess about the outcome of an event.
v To be sure of something; to be able to count on something.
v (poker) To 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.