<P> In music, metre (Am. meter) refers to the regularly recurring patterns and accents such as measures and beats . Unlike rhythm, metric onsets are not necessarily sounded, but are nevertheless expected by the listener . </P> <P> A variety of systems exist throughout the world for organising and playing metrical music, such as the Indian system of tala and similar systems in Arabian and African music . </P>

In a song that is in a meter of four each grouping of four beats is called a