περιῆν

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

Source

French (Bailly abrégé)

impf. de περίειμι¹.

Russian (Dvoretsky)

περιῆν: impf. к περίειμι I.

Dutch (Woordenboekgrieks.nl)

περιῆν imperf. van 1. περίειμι.