—v.i. 1. to work, perform, or function, as a machine does: This engine does not operate properly. 2. to work or use a machine, apparatus, or the like.
3. to act effectively; produce an effect; exert force or influence (often fol. by on or upon): Their propaganda is beginning to operate on the minds of the people. 4. to perform some process of work or treatment.
5. Surg.to perform a surgical procedure.
6. (of a drug) to produce the effect intended.
7. Mil. a. to carry on operations in war.
b. to give orders and accomplish military acts, as distinguished from doing staff work.
8. to carry on transactions in securities, or some commodity, esp. speculatively or on a large scale.
9. Informal.to use devious means for one's own gain; insinuate oneself; finagle: a man who knows how to operate with the ladies.
—v.t. 1. to manage or use (a machine, device, etc.): to operate a switchboard. 2. to put or keep (a factory, industrial system, ranch, etc.) working or in operation: to operate a coal mine. 3. to bring about, effect, or produce, as by action or the exertion of force or influence.