phase so that they vibrate in harmony. It is also defined as a synchronization of two or more rhythmic cycles. The principle of entrainment is universal, appearing in chemistry, pharmacology, biology, medicine, psychology, sociology, astronomy, architecture and more. The classic example shows individual pulsing heart muscle cells. When they are brought close together, they begin pulsing in synchrony. Another example of the entrainment effect is women who live in the same household often find that their menstrual cycles will coincide.

The history of entrainment is linked to Dutch scientist, Christian Huygens in 1665. While working on the design of the pendulum clock, Huygens found that when he placed two of them on a wall near each other and swung the pendulums at different rates, they would eventually end up swinging in at the same rate. This is due to their mutual influence on one another.

The entrainment process is quite evident in music. It is possible to have rhythmic entrainment, melodic entrainment and dynamic entrainment.