ἐπιπακτόω
From LSJ
ἐπ' αὐτὸν ἥκεις τὸν βατῆρα τῆς θύρας → you've come to the crux of the matter, come to the point, hit the nail on the head, you've come to the very threshold of the door, you are come to the very threshold of the door, you've arrived at the truth of the matter
English (LSJ)
A shut close, τὰς θύρας Ar.Fr.721.
German (Pape)
[Seite 967] zumachen, verschließen, θύρας, Ar. bei Poll. 10, 27.
Greek (Liddell-Scott)
ἐπιπακτόω: κλείω καλῶς, τὰς θύρας, «τῷ δὲ κλεῖσαι ἴσον τὸ πακτοῦν καὶ τὸ ἐπιπακτοῦν τὰς θύρας ἐστίν, ὥσπερ τῷ ἀνοίγειν ταὐτὸν τὸ λύειν, κτλ. Πολυδ. Ι΄, 27 (Ἀριστοφ. Ἀποσπ. 608).
Russian (Dvoretsky)
ἐπιπακτόω: запирать (τὰς θύρας Arph.).