定海

Proper noun

 * , encompassing the western half of and some of the surrounding islands
 * , the former separate city which served as the seat of the Zhoushan Archipelago's various governments
 * , encompassing the Zhoushan Archipelago under the Ming, early Qing, Republic, and early People's Republic
 * 1)   Dinghai Subprefecture, a former division of Zhejiang encompassing the Zhoushan Archipelago under the late Qing