ἑβδόμειος
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)
worshipped on the seventh day, epithet of Apollo, IG2.1653.
German (Pape)
[Seite 699] ὁ, Beiname des Apollo, Inscr. I p. 463; s. ἑβδομαγέτης.