operate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To perform a function; work.
• intransitive verb To perform surgery.
• intransitive verb To exert an influence.
• intransitive verb To produce a desired or proper effect.
• intransitive verb To carry on a military or naval action or campaign.
• intransitive verb Informal To conduct business in an irregular or devious manner.
• intransitive verb To control the functioning of; run.
• intransitive verb To conduct the affairs of; manage.
• intransitive verb To supply with power.

from The Century Dictionary.

• To perform or be at work; exert force or influence; act: with on or upon governing the object of the action: as, the sculptor operates on the clay or marble of which he makes his figures; a machine operates on the raw materials submitted to it.
• Specifically, in surgery, to perform some manual act upon the body of the patient, usually with instruments, with a view to restore soundness or health, or otherwise to improve the physical condition.
• To produce an effect; act; work: used absolutely.
• To produce the desired or appropriate effect; act effectively; be effectual in producing the result intended: as, the medicine operated well.
• To carry on speculative transactions; buy and sell speculatively: with in: as, to operate in stocks; to operate in oil.
• Synonyms 3 and 4. Act, Work, etc. See act.
• To effect; produce by action or the exertion of force or energy; accomplish as an agent; cause.
• To direct or superintend the working of; cause to move or perform the acts desired; work: as, to operate a machine.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To produce, as an effect; to cause.
• transitive verb To put into, or to continue in, operation or activity; to work.
• intransitive verb To perform a work or labor; to exert power or strength, physical or mechanical; to act.
• intransitive verb (Med.) To produce an appropriate physical effect; to issue in the result designed by nature
• intransitive verb To act or produce effect on the mind; to exert moral power or influence.
• intransitive verb (Surg.) To perform some manual act upon a human body in a methodical manner, and usually with instruments, with a view to restore soundness or health, as in amputation, lithotomy, etc.
• intransitive verb Brokers' Cant To deal in stocks or any commodity with a view to speculative profits.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb To perform a work or labour; to exert power or strength, physical or mechanical; to act.
• verb To produce an appropriate physical effect; to issue in the result designed by nature; especially (Med.), to take appropriate effect on the human system.
• verb To act or produce effect on the mind; to exert moral power or influence.
• verb medicine To perform some manual act upon a human body in a methodical manner, and usually with instruments, with a view to restore soundness or health, as in amputation, lithotomy, etc.
• verb To deal in stocks or any commodity with a view to speculative profits.
• verb To produce, as an effect; to cause.
• verb To put into, or to continue in, operation or activity; to work; as, to operate a machine.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb keep engaged
• verb direct or control; projects, businesses, etc.
• verb perform a movement in military or naval tactics in order to secure an advantage in attack or defense
• verb perform as expected when applied
• verb handle and cause to function
• verb perform surgery on
• verb happen