Six Pack

Defined abdominal muscles, so called because six bulges are visible (three per side) through the skin. The level of bodyfat necessary to see all six varies between individuals and the lower ones usually require the lowest bodyfat levels to bring them out (so, if a weightlifter has a little too much abdominal fat left, a weightlifter might have a "four pack" with just the upper four showing.

see the Misc.Fitness.Weights FAQ: How do I get a six-pack?