κῆτος

Beekes suggests a Pre-Greek origin.

κῆτος • (kêtos) n (genitive κήτους); third declension

1. whale, sea monster
   1. (astronomy) the constellation Cetus
2. abyss

• “κῆτος”, in Liddell & Scott (1940) A Greek–English Lexicon, Oxford: Clarendon Press
• “κῆτος”, in Liddell & Scott (1889) An Intermediate Greek–English Lexicon, New York: Harper & Brothers
• “κῆτος”, in Autenrieth, Georg (1891) A Homeric Dictionary for Schools and Colleges, New York: Harper and Brothers
• κῆτος in Bailly, Anatole (1935) Le Grand Bailly: Dictionnaire grec-français, Paris: Hachette
• κῆτος in Cunliffe, Richard J. (1924) A Lexicon of the Homeric Dialect: Expanded Edition, Norman: University of Oklahoma Press, published 1963
• G2785 in Strong, James (1979) Strong’s Exhaustive Concordance to the Bible
• Woodhouse, S. C. (1910) English–Greek Dictionary: A Vocabulary of the Attic Language‎, London: Routledge & Kegan Paul Limited, page 974
• Beekes, Robert S. P. (2010) Etymological Dictionary of Greek (Leiden Indo-European Etymological Dictionary Series; 10), with the assistance of Lucien van Beek, Leiden, Boston: Brill, →ISBN