When a piece of music is written, the meter is indicated at the beginning of the score by a time signature. The time signature usually consists of two numbers. The top number indicates how many beats are in each measure. The bottom number indicates the note value that represents each beat. For example, a 4/4 (four-four) time signature means that each measure contains four beats, and each beat is represented by a quarter note.
Meter can be duple, triple, or quadruple.
Duple meter: the pulse is divided into two beats per measure.
Examples of duple meters: 2/2 (two-two), 2/4 (two-four), 6/8 (six-eight).
Triple meter: the pulse is divided into three beats per measure.
Examples of triple meters: 3/4 (three-four), 3/8 (three-eight), 9/8 (nine-eight).
Quadruple meter: the pulse is divided into four beats per measure.
Examples of quadruple meters: 4/4 (four-four), 4/8 (four-eight), 12/8 (twelve-eight).