The early Russian explorers named the islands by this term because of four prominent volcanoes, each located on a separate island. The Aleut name Unigun (Uniiĝun in the modern Aleut orthography) was reported in 1940 by Father Veniaminov.
Russian pioneers initially labeled the islands based on four notable volcanic formations, one located on each of the individual islands. According to Father Veniaminov's account in 1940, the Aleuts referred to these islands as Unigun.