One of the mysteries of the English language finally explained.
The top of the buttocks and buttock cleft, as revealed when a person bends over or crouches down, or by low-cut or badly fitting trousers.
1980s; earliest use found in The Guardian. With allusion to the perceived propensity of builders to expose inadvertently this part of the body.
In this article we explore how to impress employers with a spot-on CV.