ἀχερωίς
From LSJ
ὁ αὐτὸς ἔφησε τὸν μὲν ὕπνον ὀλιγοχρόνιον θάνατον, τὸν δὲ θάνατον πολυχρόνιον ὕπνον → Plato said that sleep was a short-lived death but death was a long-lived sleep
Greek (Liddell-Scott)
ἀχερωίς: -ίδος, ἡ, ἀλλαχοῦ καλουμένη λεύκη, Ἰλ. Ν. 389., Π. 482· (ἐκ τοῦ Ἀχέρων, διότι ἐπιστεύετο ὅτι ἐκομίσθη ἐκ τοῦ κάτω κόσμου ὑπό τοῦ Ἡρακλέους, Παυς. 5. 14, 2· πρβλ. Νικ. Ἀλεξιφ. 13, Ἀχ. ὄχθαι): «τὴν δὲ λεύκην πεφυκέναι φασὶ πρὸς τῷ Ἀχέροντι, ὅθεν καὶ ἀχερωΐδα καλεῖσθαι παρ’ Ὁμήρῳ» Ἁρπ. ἐν λέξει λεύκη.