(Ice) hockey: The 6' radius semi-circle in front of the goal. The crease is a protected area for the goaltender. No player from the attacking team may enter the crease without the puck. If they do so and make contact with the goalie, they may receive a goaltender interference penalty.
Briefly, the NHL implemented a rule disallowing any goal scored when an attacking player entered the crease before a goal was scored. This led to endless video review and was unpopular with fans and players. The rule was discontinued after Brett Hull's Stanley Cup winning goal was scored in apparent violation of this rule. (See Buffalo sports teams are all cursed.)
The crease is painted blue beneath the ice, and is sometimes called the "blue ice" by 'hip' sportscasters. Thus, by association, the "white ice" is the area outside the crease, where adventurous goalies like Patrick Roy or Dominik Hasek may wander during play.