1. To perform a function; to work: The motor operates smoothly.
2. To perform surgery.
3. To exert an influence; such as, forces operating on the economy.
4. To produce a desired or proper effect;for example, a drug that operates quickly.
5. To carry on a military or naval action or campaign.
6. To conduct business in an irregular or devious manner; such as, drug dealers operating in residential and school areas.

To work together, act in conjunction (with another person or thing, to an end or purpose, or in some kind of work).