use tax

Definition from Nolo’s Plain-English Law Dictionary

A tax imposed by a state to compensate for the sales tax lost when an item is purchased outside of the state, but is used within the state. For example, you buy your car in a state that has no sales tax, but you live across the border in a state that does have a sales tax. When you bring your car home and register it in your state, the state taxing authority may bill you for the sales tax it would have collected had you bought the car within the state.

Definition provided by Nolo’s Plain-English Law Dictionary.