Vibrations and oscillations between a Creative Force or sound source and any object impacted by those vibrations or oscillations. The vibrating air between a sound creating violin and a passive listening ear is the media for Transmissive vibration.
Law of Force
"Energy manifests itself in three forms: Creative, the vibrating aggregate; Transmissive, being the propagation of isochronous waves through the media in which it is immersed; Attractive, being its action upon other aggregates capable of vibrating in unisons or harmony." [Keely, 1893]