Where does “Cetus” come from?

Cetus (English) comes from Latin cētus, from Ancient Greek κῆτος — whale, sea monster; abyss.

Ancestry of “Cetus”, step by step

Step	Language	Word	Meaning
1	Latin	cētus	—
2	Ancient Greek	κῆτος	whale, sea monster; abyss

Cetus — Etymology, Origin & Word History | Etymology Explorer