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.
In the early days of exploration, Russian pioneers gave these islands a name based on four distinctive volcanic peaks, one situated on each separate island. This information was documented by Father Veniaminov in his account from 1940.