tempo explained

Tempo is the speed of the beat in music, traditionally indicated by Italian terms and more precisely measured in BPM (beats per minute).‌​‍​‌​‍​‍​‍​‍​‌​‍​‌​‌​‌​‍​‍​‍​‌​‌​‍​‍​‌​‍​‍​‍​‌​‌​‌​‍​‍​‌​‍​‍​‌ Standard tempo markings form a spectrum from very slow to very fast: grave (very slow and solemn), largo (broadly), adagio (slowly), andante (at a walking pace), moderato (at moderate speed), allegretto (moderately fast), allegro (fast and lively), vivace (lively), presto (very fast), and prestissimo (as fast as possible). A metronome provides an exact tempo reference. Tempo changes within a piece include accelerando (speeding up), ritardando or rallentando (slowing down), and tempo rubato (flexible tempo for expressive purposes). The choice of tempo profoundly affects a piece's character — the same melody played adagio and allegro will convey entirely different emotions.