A gaffer in the motion picture industry and on a television crew is the head electrician, responsible for the execution (and sometimes the design) of the lighting plan for a production. The term gaffer originally related to the moving of overhead equipment to control lighting levels using a gaff. The gaffer's assistant is the best boy. Sometimes the Gaffer is credited as Chief Lighting Technician (CLT). The term has been used for the chief electrician in films since the 1930s. The Oxford English Dictionary has a citation from 1936, a 1929 book on motion picture production also uses the term.