The term FILM-LENGTH MEASURE can be solved by the crossword solution REEL, which is a four letter word. A REEL is a device used to measure the length of a film. It is typically made of metal or plastic and is used to store and transport film. The size of the REEL depends on the length of the film, with larger reels being used for longer films. Reels are also used to measure the length of audio recordings.