A beat is the basic time unit of a piece of music;; for example, each tick sounded by a metronome would correspond to a beat. More technically, "the beat is the pulse of the mensural level", also known as the beat level, the metric level at which pulses are heard as the basic unit--"the denominator of the meter signature," admitting compound meters. Depending on the context, beat may denote either
- the onset of the corresponding time unit, a point in time, the very moment when the metronome ticks, or
- the complete time interval between two consecutive taps, so to say, or
- in popular music, the whole sequence of individual beats (in the sense of meter, rhythm, groove, or riddim). In hip hop music, the term 'beat' has come to be defined as the entire instrumental, non-vocal portion of the song.
Much music is characterised by a sequence of stressed and unstressed beats (often called "strong" and "weak") organised into a meter and partially indicated by a time signature, the speed of which is determined by a tempo. In the context of a time signature, the term "beat" most often refers to the bottom number — so in 3/4, most people would consider the beat to be the 4; that is, a quarter-note, or crotchet. However, in 6/8 the dotted quarter note gets the beat rather than the eighth, for example. Musicians typically find that mentally counting a regular series of beats enables them to keep synchronised even if the music is not characterised by regular rhythm.
Metric levels faster than the beat level are division levels, and slower levels are multiple levels.