ETYM Italian, from Latin tempus. Related to Tense.
1. The rate of some repeating event; SYN. pace.
2. The speed at which a composition is to be played; SYN. pacing.
In music, the speed at which a piece should sound. Objectively, tempo corresponds to the repetition rate of an underlying beat, as established by the metronome. Subjectively, and in practice, tempo involves a balance of the mechanical beat value against the expressive demands of melody and rhythm.