A drum circle is any group of people playing (usually) hand-drums and percussion in a circle. They are distinct from a drumming group or troupe in that the drum circle is an end in itself rather than preparation for a performance. They can range in size from a handful of players to circles with thousands of participants.
In 1991, during testimony before the United States Senate Special Committee on Aging, Grateful Dead drummer Mickey Hart stated:
Typically, people gather to drum in drum “circles” with others from the surrounding community. The drum circle offers equality because there is no head or tail. It includes people of all ages. The main objective is to share rhythm and get in tune with each other and themselves. To form a group consciousness. To entrain and resonate. By entrainment, I mean that a new voice, a collective voice, emerges from the group as they drum together.