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From LSJ

αὐτὸν κέκρουκας τὸν βατῆρα τοῦ λόγου → you have struck the very threshold of the argument, you have struck the most important and chiefmost point

Source

Russian > Greek

πλάγιον, κράσπεδον, πλευρά, πλευρή, ἐπιφάνεια