RHYTHM - Sonic action in time. Or, the arrangement of durational sonic patterns or tone lengths that fall on or between a "beat".

A text summary of the clickable map above, meant for web-crawlers and other automatic tools:
rhythm is aspect of musical unity
rhythm has basic skeleton meter
rhythm has represention notation
rhythm is component of time
rhythm has role in key
rhythm element of melody
rhythm element of timbre
rhythm expresses human emotion
rhythm used to create song
rhythm has timbral resource instruments
rhythm may have temporal unit beat
rhythm has/have "treatment" style
rhythm part of tonality
rhythm part of motive
rhythm element one of Elements of Music