1. Music box (mainly American usage; e.g., Regina Music Box Co.) or musical box (mainly British usage). An instrument which plays music by the plucking of teeth on a tuned steel comb. Most commonly found in a cabinet, usually made of wood, which contains a disc or cylinder music box movement. 2. General term used by the public to describe any type of automatic musical instrument. In this usage, the term musical box (i.e., a box that produces music) would be more descriptive than music box (i.e., a box made for storing music, such as sheet music).