reformatory adj.

late 14c., reformen, "to convert into or restore to another and better form" (of strength, health, firmness, etc.), from Old French reformer "rebuild, reconstruct, recreate" (12c.) and directly from Latin reformare "to form again, change, transform, alter," from re- "again" (see re-) + formare "to form" (see form (n.)).

The meaning "change (someone or something) for the better, correct, improve; bring (someone) away from an evil course of life" is recorded from late 14c.; of governments, institutions, etc., from early 15c. Intransitive sense of "abandon wrongdoing or error" is by 1580s. Related: Reformed; reforming. Reformed churches (1580s) on the European continent were usually Calvinist as opposed to Lutheran (in France they were the Huguenots). Reformed Judaism (1843) is a movement initiated in Germany by Moses Mendelssohn (1729-1786). Reform school is attested from 1859.

adjective and noun suffix, "having to do with, characterized by, tending to, place for," from Middle English -orie, from Old North French -ory, -orie (Old French -oir, -oire), from Latin -orius, -oria, -orium.

Latin adjectives in -orius, according to "An Etymological Dictionary of the French Language," tended to "indicate a quality proper to the action accomplished by the agent; as oratorius from orator; laudatorius from laudator. The neuter of these adjectives was early employed as a substantive, and usually denoted the place of residence of the agent or the instrument that he uses; as praetorium from praetor; dormitorium from dormitor; auditorium, dolatorium.

"These newer words, already frequent under the Empire, became exceedingly numerous at a later time, especially in ecclesiastical and scholastic Latin; as purgatorium, refectorium, laboratorium, observatorium, &c." [transl. G.W. Kitchin, Oxford, 1878]