An instrumental is a musical composition or recording without lyrics, or singing, although it might include some inarticulate vocals, such as shouted backup vocals in a Big Band setting. The music is primarily or exclusively produced by musical instruments. An instrumental can exist in music notation, after it is written by a composer; in the mind of the composer (especially in cases where the composer herself will perform the piece, as in the case of a blues solo guitarist or a folk music fiddle player); as a piece that is performed live by a single instrumentalist or a musical ensemble, which could range in size from a duo or trio to a large Big Band, concert band or orchestra.
In a song that is otherwise sung, a section that is not sung but which is played by instruments can be called an instrumental interlude, or, if it occurs at the beginning of the song, before the singer starts to sing, an instrumental introduction. If the instrumental section highlights the skill, musicality, and often the virtuosity of a particular performer (or group of performers), the section may be called a "solo" (e.g., the guitar solo that is a key section of heavy metal music and hard rock songs). If the instruments are percussion instruments, the interlude can be called a percussion interlude or "percussion break". These interludes are a form of break in the song.