Dictionary entry

ὀσφύς

G. Abbott-Smith's A Manual Greek Lexicon of the New Testament with Strong's

ὀσφύς, -ύος, ἡ,

[in LXX chiefly for מָתְנַיִם, also for חָלָץ, etc.;]

the loin: Mt 3:4, Mk 1:6; metaph., περιζώννυσθαι (ἀναζ-) τ. ὀσφύας, Lk 12:35, Eph 6:14, I Pe 1:13; regarded, as by the Hebrews, as the seat of generative power, He 7:5, 10; metaph., καρπὸς τ. ὀσφύος, Ac 2:30.