1480-90; v. use of phrase in ure, en ure in use, customary < Anglo-Frenchen ure in use, at work, equivalent to enin + ure < Latinopera, plural of opus work; compare Frenchoeuvre
C15 enuren to accustom, from ure use, from Old French euvre custom, work, from Latin opera works, plural of opus
Word Origin and History for inure
v.
early 15c., in ure "in practice," from obsolete ure "work, practice, exercise, use," probably from Old French uevre, oeuvre "work," from Latin opera (see opus). Related: Inured; inuring.