углубление

From LSJ

εἰς τετρημένον πίθον ἀντλεῖν → run water into a punctured pitcher, to the perforated jar bale water, labour in vain, labor in vain

Source

Russian > Greek

κοῖλον, κοίλωμα, εἰσοχή, θέναρ, βόθρος