ἐν οἰκίᾳ τυφλῶν καὶ ὁ νυκτάλωψ ὀξυδερκής → even the day-blind is sharp-eyed in a blind house | among the blind, the one-eyed man is king
P. and V. δρέπανον, τό (Euripides, Cyclops 394).
