v.1. To exert force on something repeatedly or continuously: The plumber worked at the clog with a plunger.
2. To direct persistent or diligent effort toward something: You must keep working at your piano exercises if you want to improve.
3. To do work in some particular place: I'm working at home today. I'm working at my desk.
4. To hold a job at some place: I used to work at the hospital before I got a job at the bank.