Tempo is the aspect of rhythm that determines how fast or slow the 'beat' of the music is played. In some cases the 'beat' can be interpreted subjectively, but in most cases it is obvious what that main beat is in a given piece of music. To some degree the tempo is linked to the meter of the music. The plural of tempo is tempi. There are many tempo indications in music. The few mentioned in this class include: Adagio, Andante, Allegro, and Presto. Two other terms that are related to tempo are accelerando and ritardando.