Areas that are difficult for a goalie to cover are termed "holes." The net has four corners, and the space between the legs is termed the "five hole." The space between the goalie's stick-side arm and his body is the "six hole," leaving "seven hole" for the glove-side arm. Goals that are scored through the five hole, six hole, or seven hole are often considered to be the fault of poor goaltending.
Note: The term "six hole" is rarely ever used. For whatever reason, it is usually also referred to as the "seven hole," perhaps to emphasize the perceived lucky nature of such goals.
Sasha: "San Jose's goalie is such a sieve all of a sudden How'd that go in? Five hole?
Alex: "I thought so too, but on the replay it looks like it got deflected seven hole."