Bora-Bora (bōˈrä-bōˈrä) [key], volcanic island, 15 sq mi (39 sq km), South Pacific, in the Leeward group of the Society Islands, French Polynesia. It is a mountainous island, with Mt. Otemanu (2,379 ft/725 m) the highest peak. Bora-Bora has a good harbor, which is a large lagoon surrounded by coral islets. Copra, oranges, and vanilla are produced on the island. Tourism is a major source of commerce.