Merriam-Webster Collegiate Dictionary - aden

 geographical name  1. former British protectorate S Arabia comprising the entire S coast of what is now Yemen; became part of People's Democratic Republic of Yemen 1967 area 112,000 square miles (291,200 square kilometers)  2. former British colony SW Arabia comprising Perim Island, the city of ~, & the surrounding area; became part of People's Democratic Republic of Yemen 1967 area 75 square miles (195 square kilometers)  3. city & port S Yemen; formerly capital of People's Democratic Republic of Yemen & before that capital of ~ colony & protectorate population 240,370