Definition of bring-in
You may not be familiar with the term, as it is only found in a few poker variants that do not include the most popular variants such as Hold'em and Omaha. The bring-in is a forced bet in Seven-card stud and Razz, among others. The forced bet must be paid by the player who received the worst card preflop. This bet is always smaller than a regular bet. The bring-in is almost always paid in the first round of betting.
Additional details on the bring-in
When a player pays the bring-in, he will always have the option of raising to a full bet. The act of paying this bet is called "bringing it in" or "bringing in the pot". In Seven-card stud, to determine who will pay the bring-in, all players are dealt cards that are visible. The player with the worst card will be the bring-in. In case of a tie, the worst card will be determined by suit according to the following chart (from lowest to highest suit): clubs, diamonds, hearts, spades. So, if one player has the deuce of spades and another has the deuce of clubs, the player with the deuce of clubs is the bring-in.