Six Pack

People Photography Slim Poster: The 'six-pack', also known colloquially as 'washboard abs' and 'abs of steel' as well as other nicknames refers to a well defined set of abdominal muscles. The abdominal muscles, correctly called the rectus abdominis muscle is a paired muscle that runs vertically on the abdominal wall and helps to control posture as well as protect the body cavity. The sight of well defined abs has become synonymous with fitness and good physique.