Origin and history of statutory

c. 1300, "a law of the land, a ruler's decree," from Old French statut, estatut, estatu "(royal) promulgation, (legal) statute," from Late Latin statutum "a law, decree," noun use of neuter past participle of Latin statuere "enact, establish," from status "condition, position," from stare "to stand" (from PIE root *sta- "to stand, make or be firm").

Especially, later, "an ordinance promulgated by a legislative body" (late 14c.). As an adjective designating units of measure or weight as set by statute, 1580s.

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]