μυριετής
From LSJ
Ἐάν γάρ ἀποδιδῷ τις τί ἐστιν αὐτῶν ἑκατέρῳ τό ζῴῳ εἶναι, ἴδιον ἑκατέρου λόγον ἀποδώσει (Aristotle, Categoriae 1a) → For if anyone gives an explanation of what it is for each of them to be an animal, he will give the same explanation of each
English (LSJ)
ές,
A of 10,000 years: of countless years, χρόνος A.Pr.94 (anap.), Pl.Epin.987a; βίος Arist.GA745a33; of a man, AP9.242 (Antiphil.).