If you run an errand for someone, you do or get something for them, usually by making a short trip somewhere.

What does it mean to run a errand?

Go to perform a commission, as in I spent the morning running household errands—to the cleaners, the supermarket, the hardware store. [

Is run an errand an idiom?

Run an errand is a common phrase in English that is not always recognized as an idiom. To run an errand means to complete one specific errand; to run errands means to complete more than one. The errand referred to in running an errand is usually to go to a store to buy something.