an island in SW Alaska, in the E part of the Aleutian Islands: largest and easternmost of the Aleutian Islands. ab. 70 mi. (110 km) long and 20 mi. (32 km) wide.
U·ni·mak Island (yōō'nə-māk') An island of southwest Alaska in the eastern Aleutian Islands separated from the Alaska Peninsula by a narrow strait. It is the largest island of the group.