“Voluntary Associations: Any public, formally constituted, and non-commercial organization of which membership is optional, within a particular society. Examples include churches, political parties, pressure groups, leisure associations or clubs, neighborhood groups, and (sometimes) trade unions and professional associations. In some theories of democracy, emphasis is placed on the important role such groups can play in fostering participation in the civil society, and thus in maintaining social order.”
Excerpted from: Marshall, Gordon, ed. Oxford Dictionary of Sociology. New York: Oxford University Press, 1994.