ey·ak \ˈīˌak, ˈēˌ-\noun (pluraleyakoreyaks) Usage: usually capitalized Etymology: from Eyak, lake, village, & river in Alaska 1. a.: an Indian people of the Copper river delta in Alaska b.: a member of such people 2. a.: the language of the Eyak people b.: a language stock of the Na-dene phylum comprising only Eyak