επικτίζω

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

Source

Greek Monolingual

ἐπικτίζω (AM)
1. χτίζω ξανά πάνω σε προϋπάρχοντα θεμέλια («καλοῦσι δὲ παλαιὰν Ἐρέτριαν, ἡ δὲ νῦν ἐπέκτισται», Στράβ.)
Ι μσν. κτίζω ως προσθήκη ανυψώνοντας κτίσμα
αρχ.
ιδρύω, χτίζω («πόλεις ἑλληνίδας ἐπικτίζοντες ἀγρίοις ἔονεσι», Πλούτ.).