1. an island off S Florida, in the Gulf of Mexico. 4 mi. (6.4 km) long; 2 mi. (3.2 km) wide.
2. a seaport on this island: the southernmost city in the U.S.; naval base. 24,292.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.