im·pound / imˈpound/ • v. [tr.] 1. seize and take legal custody of (something, esp. a vehicle, goods, or documents) because of an infringement of a law or regulation: vehicles parked where they cause an obstruction will be impounded.2. shut up (domestic animals) in a pound or enclosure. ∎ (of a dam) hold back or confine (water).DERIVATIVES: im·pound·a·ble adj.im·pound·er n.im·pound·ment n.