chain of islands extending c. 1,200 mi (1,931 km) southwest from the tip of the Alaska Peninsula: constituting, with the W half of the Alaska Peninsula, a district of Alas.: 15,501 sq mi (40,147 sq km)
A chain of rugged volcanic islands of southwest Alaska curving about 1,850 km (1,150 mi) west from the Alaska Peninsula and separating the Bering Sea from the Pacific Ocean. The islands are part of the Aleutian Range, a volcanic mountain chain extending along the Alaska Peninsula to the southern coast near Anchorage.
Possibly from Chukchi aliat (“island”).