From the verb phrase lock up.
lockup (plural lockups)
- (slang) A jail cell, or a period of incarceration.
- He's in lockup for 30 days for drunk and disorderly.
- (Britain, chiefly) A storage unit with a door secured by a padlock or deadbolt; a garage
- Joe keeps his other car in a lockup downtown.
- (marketing) A fixed layout involving one or more logos and possibly related text.
prison — see prison