Lexicon :: Strong's G3751 - osphys

ὀσφύς (or ὀσφύς, so R Tr in Ephesians 6:14; G in Matthew 3:4; cf. Chandler §§ 658, 659; Tdf. Proleg., p. 101), ὀσφύος, ἡ, from Aeschylus and Herodotus down;
1. the hip (loin), as that part of the body where the ζώνη was worn (the Sept. for מָתְנַיִם): Matthew 3:4; Mark 1:6; hence, περιζωννυσθαι τάς ὀσφύας, to gird, gird about, the loins, Luke 12:35; Ephesians 6:14; and ἀναζωννυσθαι τάς ὀσφύας (to gird up the loins), 1 Peter 1:13; on the meaning of these metaphorical, phrases see ἀναζώννυμι.
2. a loin, the Sept. several times for חֲלָצַיִם, the (two) loins, where the Hebrews thought the generative power (semen) resided (?); hence, καρπός τῆς ὀσφύος, fruit of the loins, offspring, Acts 2:30 (see καρπός, 1 at the end); ἐξέρχεσθαι ἐκ τῆς ὀσφύος τίνος, to come forth out of one's loins i. e. derive one's origin or descent from one, Hebrews 7:5 (see ἐξέρχομαι, 2 b.); ἔτι ἐν τῇ ὀσφύϊ τίνος, to be yet in the loins of someone (an ancestor), Hebrews 7:10.

BLB Scripture Index of Thayer's