One of the mysteries of the English language finally explained.
Military slang. A message carried by aircraft (also occasionally military) personnel, designed to protect them from harm if stranded in hostile territory, typically by offering a reward to local people for helping the service personnel to survive, or to return to their own lines unharmed. Also called gooly chit (British).
2historical British slang. A document signed by a person before embarking on a flight, surrendering the right to take legal action in the event of an accident (now historical). Now in extended use.
1920s; earliest use found in World's Work. From blood + chit.
blood chit/ˈblʌd tʃɪt/
In this article we explore how to impress employers with a spot-on CV.