Definition of the word belt up

The expression "belt up" is a regional variant of the phrase "pipe down" or "shut up" in British English. Its roots can be traced back to the early 20th century when it was commonly used by sailors in the Royal Navy. The word "belt" in this context is an abbreviated form of "girdle" or "waistcoat," which were thick leather or canvas straps worn around the waist to secure clothing, particularly during sports or industrial activities. In naval slang, "belt up" was a command given by an officer to a sailor or a group of sailors to remain silent or lessen their noise level, particularly in situations where covert operations were being carried out or communication was required over long distances. The phrase became popular outside the navy around the 1920s and 1930s and was often used in British popular culture, notably in films and theatre plays. Over time, the meaning of the term has evolved, and it is now commonly used as a colloquial expression to mean "shut up" or "stop talking" in daily conversation.