pluralism (n.)

1818, as a term in church administration, "the holding by one person of two or more offices at the same time," from plural + -ism. Attested from 1882 as a term in philosophy for a theory which recognizes more than one ultimate principle. In political science, attested from 1919 (in Harold J. Laski) in the sense of "theory which opposes monolithic state power." General sense of "toleration of diversity within a society or state" is from 1933. Related: Pluralist (1620s, in the church sense); pluralistic.