δραστοσύνη
From LSJ
εἰ ἀποκρυπτόντων τῶν Μήδων τὸν ἥλιον ὑπὸ σκιῇ ἔσοιτο πρὸς αὐτοὺς ἡ μάχη καὶ οὐκ ἐν ἡλίῳ → if the Medes hid the sun, the battle would be to them in the shade and not in the sun
English (LSJ)
v. δρηστοσύνη.
Greek (Liddell-Scott)
δραστοσύνη: ἴδε ἐν λ. δρηστοσύνη.
Russian (Dvoretsky)
δραστοσύνη: эп.-ион. δρηστοσύνη (ῠ) ἡ служение, служба, работа Hom.