κατακρῆθεν
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
English (LSJ)
Adv., better written divisim κατὰ κρῆθεν,
A v. κράς 11.
Greek (Liddell-Scott)
κατακρῆθεν: Ἐπίρρ., βέλτιον γραφόμενον διῃρημ. κατὰ κρῆθεν, κατὰ κεφαλῆς, ἀπὸ τῆς κεφαλῆς κάτω, πάντοθεν, παντελῶς, ἴδε ἐν λ. κρὰς ΙΙ.
Greek Monotonic
κατακρῆθεν: επίρρ., καλύτερο κατὰ κρῆθεν, βλ. κράς II.
