Talmida of Lesser of two Weevils has provided the answer to my "dolphin" quandry:

Ono, I found your answer! My friend Simon the polyglot found me the Greek word here."kêtos , eos, to,

A. any sea-monster or huge fish, delphinas te kunas te kai ei pothi meizon helêisi kêtos Od.12.97 , cf. 5.421, Il.20.147, Mosch.2.116; of seals, Od.4.446,452; of the monster to which Andromeda was exposed, E.Fr.121, cf. Ar.Nu.556, Th.1033; of the tunny, Archestr. Fr.34.3.
2. in Natural History, of the spouting cetacea, [p. 950] Arist.HA566b2, PA669a8, 697a16.
II. name of a constellation, Arat.354, Eudox. ap. Hipparch.1.2.20."
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So "any sea monster or huge fish". Some people translate it "whale", some "dolphin".