Five-hole

The five-hole is the gap between a goaltender's leg pads, right between the knees. The name comes from the old numbering of a goalie's openings: glove high and low, blocker high and low, and the fifth, the hole down the middle. Shooters who can read a goalie dropping early into the butterfly aim for it, and a five-hole goal is the most quietly humiliating way for a netminder to get beaten. More on the term's origin at Wikipedia.