1. To perform surgery on someone or an animal. The doctors are operating on me tomorrow morning, so I'm not allowed to eat or drink anything before then. They had to operate on my dog because something had become lodged in his intestines.

2. To work on or tinker with something. Tom's in the living room operating on the television, but I'm not holding my breath that he can fix it. Before you go operating on the washing machine, why don't you troubleshoot what's wrong with it.

3. To have some established stance, position, or viewpoint from which someone or something functions. If you operate on the assumption that people are trying to take advantage of you, then you'll never make any meaningful connections with anyone. We've always operated on the belief that superior customer service will allow us to compete with the bigger corporations we've been competing with.