Contain

This term refers to the strategy where one player places his army outside hits opponent's base rather than attacking his opponent directly. The general idea is to isolate the opponent inside his main base, and thus to claim map control. If successful, a contain allows a player to safely expand while preventing his opponent from expanding. The goal is usually long-term starvation: if the containing player expands, then the contained player will rapidly fall behind economically, and eventually be run over by wave after wave of units.

Good contains are very difficult to break, because the contained player must attack a standing army, and the containing player can set the battle up to be as advantageous as possible. For example, in a terran contain, the containing player will probably have siege tanks in siege mode, turrets, and spider mines set up.