The word ante comes from the Latin "ante" meaning "before". The bet is being done before the deal, hence the name.
Antes are most often used in games of 7-Stud, but they now being more frequently used as a supplementary feature in games that traditonally use blinds (such as Hold 'em) lately, in particular in the later rounds of tournaments.
An ante is typically much smaller than even the minimum normal bet at the game. For instance, a typical ante at a $4/$8 stud game might be $1. In a $20/$40 Hold 'em game, the ante might be $5 (i.e. one eighth of the big blind). In cash games at physical casinos, it is not usually more than a single chip of the smallest denomination in use on the table.
Antes are used for two basic reasons:
- In some games, such as 7-Stud, which have no blinds, antes are used to build the initial pot. Without an ante, there would be no real incentive for a player to wager on their hand, since there would be nothing to win.
- In games like Hold 'em that don't traditionally use antes, antes are used to speed up action by "punishing" players who don't play enough hands. Antes typically double (approximately) the amount of forced bets a player makes. With antes constantly chipping away at a player's chip stack, they will be required to play more hands in order to recover those chips. This generates more action, and also speeds up the rate at which players bust out in a tournament.