An improvement (or an intended improvement) in the existing form or condition of institutions or practices, etc.; intended to make a striking change for the better in social, political or religious affairs or in the conduct of persons or operation of organizations.

(historical) The religious movement initiated in the 16th century against the Roman Catholic Church.

plural of reformation

Of or pertaining to reformation

The change of something that is defective, broken, inefficient or otherwise negative, in order to correct or improve it

(transitive) To put into a new and improved form or condition; to restore to a former good state, or bring from bad to good; to change from worse to better

a political movement/party

Of Reform Judaism, its tenets, or its adherents.

plural of reform

Third-person singular simple present indicative form of reform