\Con`gre*ga"tion*al*ism\, n.
1. That system of church organization which vests all
   ecclesiastical power in the assembled brotherhood of each
   local church.
2. The faith and polity of the Congregational churches, taken
   collectively.
Note: In this sense (which is its usual signification)
      Congregationalism is the system of faith and practice
      common to a large body of evangelical Trinitarian
      churches, which recognize the local brotherhood of each
      church as independent of all dictation in
      ecclesiastical matters, but are united in fellowship
      and joint action, as in councils for mutual advice, and
      in consociations, conferences, missionary
      organizations, etc., and to whose membership the
      designation ``Congregationalists'' is generally
      restricted; but Unitarian and other churches are
      Congregational in their polity.