In music and music theory, the beat is the basic unit of time, the pulse (regularly repeating event), of the mensural level (or beat level). The beat is often defined as the rhythm listeners would tap their toes to when listening to a piece of music, or the numbers a musician counts while performing, though in practice this may be technically incorrect (often the first multiple level). In popular use, beat can refer to a variety of related concepts, including pulse, tempo, meter, specific rhythms, and groove.
Beats are related to and distinguished from pulse, rhythm (grouping), and meter:
Meter is the measurement of the number of pulses between more or less regularly recurring accents. Therefore, in order for meter to exist, some of the pulses in a series must be accented—marked for consciousness—relative to others. When pulses are thus counted within a metric context, they are referred to as beats.— Leonard B. Meyer and Cooper (1960)
Metric levels faster than the beat level are division levels, and slower levels are multiple levels. Beat has always been an important part of music. Some music genres such as funk will in general de-emphasize the beat, while other such as disco emphasize the beat to accompany dance.