What does "bonded" mean?

Bonded: Placed under, or covered by, a bond, as for the payment of duties, or for conformity to coertain regulations. Bonded goods, goods placed in a bonded warehouse; goods, for the duties on which bonds are given at the customhouse. -- Bonded warehouse, a warehouse in which goods on which the duties are unpaid are stored under bond and in the joint custody of the importer, or his agent, and the customs officers.