The time signature is used in Western rhythmic notation to specify the basic rhythm of a piece of music, also known as its meter. A time signature is a fraction. The denominator indicates which note is the beat. If the denominator is 2, the half note is one beat; if the denominator is 4, the quarter note is one beat; and so on. The numerator indicates the number of beats in each measure.
Some standard time signatures in Western music are