Abbott-Smith Manual Greek Lexicon
ὀσφύς (G3751)
8 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 .
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain