The first bet you place in table poker, before the deal.
In Three Card Poker everyone with an Ante gets three cards and chooses Play or Fold. Folding loses the Ante. If the dealer does not qualify, a played hand wins the Ante 1:1 (in UTH the Ante is returned; in Casino Hold'em it is paid on the paytable). This is different from the poker ante (a forced bet from everyone).