Impound/ɪmˈpaʊnd/ Definition 1 of 2Pro Tip 1/3Legal Authority Impound is often used in legal contexts where authorities enforce rules or laws. If you park illegally, your car may be impounded. Pro Tip 2/3Temporary Custody Impounded items are held for a period of time but not necessarily forever. Her passport was impounded during the investigation. Pro Tip 3/3Security Measure Impounding is usually for safety or as part of an investigation. The hazardous materials were impounded by the fire department.