εἰκοσαέτης

From LSJ

τούτου δὲ συμβαίνοντος ἀναγκαῖον γίγνεσθαι πάροδον καὶ τροπὰς τῶν ἐνδεδεμένων ἄστρων → but if this were so, there would have to be passings and turnings of the fixed stars

Source

French (Bailly abrégé)

ης, ες :
de vingt ans.
Étymologie: εἴκοσι, ἔτος.