出典:Wiktionary
ceno- + -zoic; from Ancient Greek καινός (kainós, “new”) + ζωή (zōḗ, “life”)
The pronunciations with /k/ were the only ones in use until the twentieth century. The forms with /s/ were considered incorrect pronunciations until at least the 1950s[1] and still may be by some speakers today.
Cenozoic