From an unused root meaning to be soft; the thigh (from its fleshy softness); by euphem. The generative parts; figuratively, a shank, flank, side -- X body, loins, shaft, side, thigh.
H3409. yarek
יָרֵךְ noun feminineNumbers 5:27 thigh, loin, side, base (Late Hebrew id.; Aramaic יַרְכָּא; Zinjirli ירך loin; Assyrian arku, arkâtu, back, rear, hereafter DlHWB 242; Arabic hip) — absolute יָרֵךְ Judges 15:8 6t.; construct יֶ֫רֶךְ Genesis 24:9 11t. + 2 Samuel 3:27 (see below); suffix יְרֵכִי Genesis 24:2; 47:29; יְרֵכֵךְ Numbers 5:21; יְרֵכוֺ Genesis 32:26 6t.; יְרֵכָהּ Exodus 25:31+ 3t.; dual יְרֵכַיִם 28:42; suffix יְרֵכַיִךְ Cant 7:2; —
1 thigh,
a. outside of thigh, where sword was worn, עַליְֿרֵכוֺ חֶרֶב שִׂים Exodus 32:27 (E); יְמִינוֺ עַליֶֿרֶךְ אֹתָהּ וַיַחְגֹּר Judges 3:16 and he girded it upon his right thigh, 3:21; Psalm 45:4; Song of Solomon 3:8; הַיָּרֵךְ כַּף Genesis 32:33 hollow of the thigh, Genesis 32:26 (twice in verse); Genesis 32:33 (all J); יְרֵכַיִךְ חַמּוּקֵי Cant 7:2 the roundings of thy thighs; וְעַדיְֿרֵכַיִם מִמָּתְנַיִם Exodus 28:42 (P); "" בֶּטֶן Numbers 5:21-22, 27 (P); עַליְֿרֵכוֺ צֹלֵעַ Genesis 32:32 (J), limping upon his thigh; עַליָֿרֵח סָפַק Jeremiah 31:19 and (with אֶלֿ) Ezekiel 21:17, smite upon, thigh, in token of consternation; יָרֵךְ עַלֿ שׁוֺק אוֺתָם וַיַּךְ Judges 15:8 and he smote them, hip upon thigh, a great slaughter.
b. thigh = loins, as seat of procreative power (RSK. 34; Semitic i, 360 (380)) ירך יֹצְאֵי those proceeding from the loins of any one Genesis 46:26; Exodus 1:5 (both P), Judges 8:30; hence ירך תַּחַת יַד שִׂים place the hand under thigh, in taking oath Genesis 24:2, 9 (J), 47:29.
2 side (flank) of altar 2 Kings 16:14; Leviticus 1:11 (P); of tabernacle Exodus 40:22, 24; Numbers 3:29, 35 (all P); also הַשַּׁעַר יֶרֶךְ (for הַשּׁ ׳תּוֺךְ ᵑ0) ᵐ5 Th We Dr Bu Kit.
3 base (loins) of candlestick Exodus 25:31; 37:17; Numbers 8:4 (all P).