Tempo refers to the speed or pace at which a piece of music is played. It is typically measured in beats per minute (BPM), indicating how many beats occur in one minute. A faster tempo results in a lively and energetic feel, while a slower tempo creates a more relaxed or somber atmosphere. In music notation, tempo is often indicated at the beginning of a score using terms like Allegro for fast, Andante for moderate, and Largo for slow. Musicians use a metronome, a device that produces a steady beat, to help maintain the desired tempo during practice and performance.