operate v.

late 14c., "action, performance, work," also "the performance of some science or art," from Old French operacion "operation, working, proceedings," from Latin operationem (nominative operatio) "a working, operation," noun of action from past-participle stem of operari "to work, labor" (in Late Latin "to have effect, be active, cause"), from opera "work, effort," related to opus (genitive operis) "a work" (from PIE root *op- "to work, produce in abundance").

The surgical sense of "act or series of acts performed upon a patient's body," usually with instruments, is first attested 1590s. The military sense of "act of carrying out a preconcerted series of movements" is by 1749.

Proto-Indo-European root meaning "to work, produce in abundance."

It forms all or part of: cooperate; cooperation; copious; copy; cornucopia; hors d'oeuvre; inure; maneuver; manure; oeuvre; office; official; officinal; omni-; omnibus; omnium gatherum; op. cit.; opera; operate; operation; operose; optimism; optimum; opulence; opulent; opus; Oscan.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit apas- "work, religious act," apnas- "possession, property;" Hittite happina- "rich;" Avestan huapah- "doing good work, masterly;" Latin opus "a work, labor, exertion;" Greek ompne "food, corn;" Old High German uoben "to start work, to practice, to honor;" German üben "to exercise, practice;" Dutch oefenen, Old Norse æfa, Danish øve "to exercise, practice;" Old English æfnan "to perform, work, do," afol "power."