We measure rhythm by using a meter. Meter is the division of a constant measurement that compares the duration of a sound to others.
Meter is to music as distance is to travel.
Each basic unit in the meter is called beat. Allegro, meaning lively, also refers to a rate of about 112 to 130 beats per minute. Melody is an organized set of sounds recognizable as a unit. Harmony can be categorized in many divisions according to Tonality and Cultural derivation. Sound production can be divided in Human Voice, Percussion, Single Reed Wind Instruments, Double Reed Wind Instruments, Wood Wind Instruments, Brass Wind Instruments, Plucked String Instruments, Bowed String Instruments, Hammered String Instruments, and Electronic.