mid-14c., from O.Fr. conformer "make or be similar" (13c.), from L. conformare "to fashion of the same form," from com- "together" + formare "to form." Sense of "to comply with the usages of the Church of England" is from 1610s; hence conformist (1630s), opposed to non-conformist or dissenter. Related: Conformance (c.1600).