1. A former British colony and protectorate of southern Arabia, part of South Yemen (now Yemen) since 1967.

2. A city of southern Yemen on a peninsula projecting into the Gulf of Aden. One of the chief ports of southern Arabia since ancient times, it became a major trading and refueling station after the opening of the Suez Canal in 1869. Aden was the capital of South Yemen from 1967 until 1990.