Tempo
Tempo is the speed of the beat: how fast one, two, three, four goes by. It is given as a metronome number or as an Italian word.
Musicians set the tempo with a metronome. Its number tells how many beats come in one minute: 60 means one beat every second, 120 is twice as fast. In written music the tempo stands above the first measure: a quarter note, an equals sign and the number, for example ♩ = 60.
Often the tempo is given as a word instead, usually in Italian. Adagio: slowly. Andante: calmly, at a walking pace. Moderato: at a moderate speed. Allegro: fast and cheerful. On the metronome they run roughly from 60 to 140 beats per minute.
Tempo changes neither the notes nor the rhythm — the same tune sounds calm at a slow tempo and lively at a fast one. When learning, play slower than written and speed up only once the notes are secure.
What it sounds like
A slow tempo feels like a stroll, a fast one like a run. The notes are the same; only how quickly they arrive changes.
Where it is taught: the studio’s interactive textbook, chapter 18, “Tempo, repeats and form”.