the thigh: the fleshy upper part of the leg, and, by extension, the source of a person's children and the side or base of a structure
TranslatabilityPartialCertaintyStrong
At its core this word names the thigh, the large fleshy upper part of the leg. It is where a soldier straps his sword or dagger, the joint Jacob dislocated when he wrestled through the night, and the part a mourner strikes with the flat of the hand when grief or shame overwhelms him.
From that concrete body part the word reaches in two directions. Because the thigh sits beside the reproductive organs, it becomes a discreet way of naming the source of one's offspring: a family line is described as "those who came out of his thigh," and a solemn oath is sealed by placing a hand under the thigh. In the ordeal for a wife suspected of unfaithfulness, the curse that strikes her "thigh" is widely understood to reach her power to bear children.
In a second direction the word moves from the body to buildings and furnishings. Just as the thigh is the fleshy side of a person, so this word names the side or flank of the altar and the tent of worship, and the upright base or shaft of the golden lampstand. English needs several words for all of this, but in Hebrew it is one word holding one picture: the thigh and the side region it stands for.
Nuances
1athe thigh or upper leg, the muscled part where a sword is worn and which can be struck or injured
the Hebrew word also names the source of one's children and the side or base of a structure, meanings the anatomical word cannot carryGen 46:26Exo 40:22
Both
both name the fleshy upper part of the leg, the place a weapon is worn or an injury fallsGen 32:25Jdg 3:16
the Hebrew word is concretely the thigh, a specific body part, even where it points to the reproductive region, not a vague term for the midsectionGen 32:25
Both
both can name the reproductive region as the source from which a person's descendants comeGen 46:26Jdg 8:30
Only loins
the English "loins" is archaic and imprecise, and can suggest the waist or lower back generally rather than the specific thigh region
the Hebrew word is a body word, the thigh or flank, carried over to a structure, so it pictures a side the way a leg is the side of a bodyGen 32:25
Both
both locate something along the flank or edge of a thing, such as the north side of the altar or tentExo 40:22Lev 1:11
Only side
the English "side" is a plain word for position with no bodily image behind it
How yarekh differs from similar Hebrew words
מָתְנַיִםthe loins or waist as the seat of physical strength, the part one girds for work or battle, whereas the thigh word names the upper leg itself and the source of one's children
Names the thigh and upper leg as the place where a sword or weapon is strapped, hanging at the side of the body.Jdg 3:16Sng 3:8Psa 45:3
Serves as a discreet term for the seat of reproduction, the part of the body from which a person's descendants come.Gen 46:26Exo 1:5Jdg 8:30
Is the body part touched in the solemn oath of putting a hand under the thigh.Gen 24:2Gen 24:9Gen 47:29
Names the side or base of an object, such as the shaft from which the branches of the lampstand extend.Exo 25:31Exo 37:17Num 8:4
Both
Both name a region of the lower body that a garment covers, as when the priests' linen breeches reach from the waist down over the upper legs.Exo 28:42
Is the lower back where a belt is fastened and the robe is tucked up to free a person to run, work, or fight.Exo 12:111Ki 18:462Ki 4:29
Stands for physical strength and steadiness, so that to break or weaken it is to cripple a person's power.Deu 33:11Pro 31:17Nam 2:1
Is the body's middle that buckles in terror or grief, gripped by pain or wrapped in sackcloth.Isa 21:3Jer 48:37Ezk 21:6
יַרְכָהthe closely related feminine form, but it means the far or innermost part (the recesses of a cave, the depths of the earth or pit, the far north, the rear of the tent), not the thigh or the outward side
Names a concrete body part, the thigh or upper leg of a person or animal, the place where a sword is strapped and where Jacob's hip was wrenched in the night wrestling.Gen 32:25Jdg 3:16Psa 45:3
Stands for the loins as the source of a man's offspring, so his descendants are described as those who came out of his thigh.Gen 46:26Exo 1:5Jdg 8:30
Names the spot touched in an oath, the hand laid under the thigh to seal a solemn promise.Gen 24:2Gen 24:9Gen 47:29
Extends to the base or shaft of a crafted object, the central stem of the golden lampstand from which its branches and cups rise.Exo 25:31Exo 37:17Num 8:4
Both
Both grow from the same root and can name a side of the sanctuary, marking where a part of its structure or furniture stood.Exo 40:22Exo 26:22
Names the remotest reaches of a wide region, the ends of the earth, the recesses of the far north, the distant heights of Lebanon.Jer 6:22Psa 48:2Isa 37:24
Names the innermost recess of an enclosed space, the deep back of a cave or the lowest hold of a ship, the hidden spot a person withdraws into.1Sa 24:3Jon 1:5Amo 6:10
Marks the rear or hindmost part of a building, the back end of the tabernacle and of the temple, the side opposite the entrance.Exo 26:221Ki 6:16Exo 36:27
Names the depths of the pit, the farthest recesses of the grave where the slain are laid.Isa 14:15Ezk 32:23
It is the body part touched in the most solemn kind of oath, where a servant or a son puts his hand under his master's thigh and swears.Gen 24:2Gen 24:9Gen 47:29
It is where a weapon hangs, so a sword strapped on the thigh is the picture of a man armed and ready.Exo 32:27Jdg 3:16Jdg 3:21Psa 45:3Sng 3:8
It stretches beyond people to objects, naming the flank or side of a building or a piece of furniture, such as the north side of the tabernacle or the shaft and sides of the lampstand.Exo 25:31Exo 40:22Exo 40:24Lev 1:11Num 3:292Ki 16:14
It borders the private area of the body, so it is the part the priests' linen shorts must cover and the part named in the ordeal for a wife suspected of unfaithfulness.Exo 28:42Num 5:21Num 5:22Num 5:27
It names the hip socket that can be knocked out of joint and leave a person limping for good.Gen 32:25Gen 32:31Gen 32:32
Both
Both are plain anatomy words for a part of the leg, used with no figure of speech at all when a writer simply reports what happened to someone's body.Deu 28:35Jdg 15:8Sng 7:1
Both stand in for the family line and the arrival of children: a newborn is received onto the knees of the one who claims it, while descendants are described as coming out of a man's thigh.Gen 30:3Gen 50:23Gen 46:26Exo 1:5Jdg 8:30
Both are places on the body where terror and grief become visible in the prophets, with knees that go slack or knock together and a thigh that gets struck in shame and mourning.Ezk 7:17Ezk 21:7Nam 2:10Ezk 21:12Jer 31:19
This is the joint that bends in kneeling, the ordinary posture for prayer, pleading, and surrender before God or a king. The word rendered "thigh" never carries that posture.1Ki 8:54Ezr 9:5Isa 45:23Dan 10:102Ki 1:13
It is the standard gauge of a person's physical strength: knees that are steadied and propped up when someone is strong, and that sag or wobble when strength runs out.Job 4:4Isa 35:3Psa 109:24
It doubles as a lap, the place where a person sits, sleeps, or is held.Jdg 16:192Ki 4:20Gen 48:12
It names the low crouch a person drops into, as when soldiers go down on all fours to drink from a stream.Jdg 7:5Jdg 7:61Ki 18:42
It works as a rough measure of depth, marking how high water has risen up a wading person.Ezk 47:4
Names the upper leg as an actual limb with a joint and flesh that can be damaged: Jacob's hip is wrenched out of place and leaves him limping, and Israel still avoids the sinew at that joint.Gen 32:25Gen 32:31Gen 32:32
Is where a sword or dagger is strapped so it hangs ready against the leg, whether hidden under a robe or worn openly by a king and his guard.Jdg 3:16Jdg 3:21Exo 32:27Psa 45:3Sng 3:8
Is the spot a servant lays his hand on to swear the most binding kind of promise, a gesture reserved for oaths about a family's future.Gen 24:2Gen 24:9Gen 47:29
Reaches beyond bodies to objects, naming the base or shaft a lampstand stands on and the flank of the tent or the altar, so a thing can have a leg or a side just as a person does.Exo 25:31Num 8:4Exo 40:22Lev 1:11Num 3:29
Both
Both stand in for the place a man's children come from, so descendants are spoken of as coming out of his loins or out of his thigh rather than named directly.Gen 35:111Ki 8:19Gen 46:26Exo 1:5Jdg 8:30
Both name the lower body as the place anguish is felt and made visible: hands clutched to the loins like a woman in labor, or a hand struck against the thigh in grief and dismay.Jer 30:6Jer 31:19Ezk 21:12
Names the lower back and hips, the place a belt is cinched, so the word supplies the standard call to brace for hard effort: "gird up your loins like a man" means tighten your clothing and be ready to answer.Job 38:3Job 40:7
Because the belt sits here, the word carries what a person is fitted out with: an army whose belt is never loosened is one that never tires, and the promised ruler wears rightness itself as the belt at his waist.Isa 5:27Isa 11:5
Marks the part of the body a garment is wrapped and tied around, so it is where warmth from a gift of wool is felt and where the cloth of mourning is fastened.Job 31:20Isa 32:11
Stands for a person's own children, the descendants pictured as having come out of his thigh, that is, from his own body.Gen 46:26Exo 1:5Jdg 8:30
The body part touched in the most solemn oath, where a servant places his hand under his master's thigh as he swears.Gen 24:2Gen 24:9Gen 47:29
The place a fighter straps his sword or dagger, so it becomes shorthand for a warrior armed and ready.Jdg 3:16Psa 45:3
Stretched beyond the body to name parts of structures: the side or flank of the tabernacle and altar, and the central shaft of the lampstand.Exo 40:22Exo 25:31
Struck with the hand as a gesture of grief and shame.Jer 31:19Ezk 21:12
Both
Both name the same body part, the upper leg, the fleshy thigh of a person.Sng 7:1Rev 19:16
In its single New Testament appearance the thigh is the visible place where the returning King's royal name and title are written for everyone to read.Rev 19:16
ὀσφῦςGreek“loins”the Greek word for the loins, which carries the reproductive sense of the Hebrew word in phrases like the offspring who come from one's loins
Names the literal upper leg as a distinct joint, the hip that can be struck a heavy blow or wrenched out of its socket.Gen 32:25Gen 32:31Jdg 15:8
Extends beyond the body to the side or base of a made object: the flank of the tabernacle, the side of the altar, the shaft of the lampstand.Exo 25:31Exo 40:22Lev 1:11
Anchors set gestures: a hand laid under the thigh to seal a solemn oath, and a hand struck against the thigh in grief and shame.Gen 24:2Gen 24:9Jer 31:19
Both
Both name the lower body as the source of a person's descendants, so a man's offspring are said to come out of his loins.Act 2:30Heb 7:10Gen 46:26
Both mark the place at the waist and thigh where a belt is fastened or a sword is hung, the spot you gird before setting out.Mat 3:4Psa 45:3Exo 32:27
Girding the loins becomes a figure for being ready and self-controlled: dressed for action, alert, and clear in mind rather than dozing.Luk 12:35Eph 6:141Pe 1:13
What scholars say about yarekh
The standard lexica (BDB, HALOT, DCH) treat ירך as a single noun with a coherent range rather than as homonyms: the thigh or upper leg; by euphemism the loins as the seat of procreative power, seen in the descent formula "those who came out of his thigh" (Genesis 46:26;Exodus 1:5;Judges 8:30) and in the oath ceremony of placing a hand under the thigh (Genesis 24:2, 9; 47:29); and, transferred to objects, the side or flank of the altar and tent and the base or shaft of the lampstand (Exodus 25:31; 40:22; Leviticus 1:11). TDOT and TWOT trace the metaphorical extension from the body to architecture and note the reticent, euphemistic force of the term. The reproductive reference of the affected "thigh" in the ordeal of Numbers 5:21-27 is widely accepted, with the affected organ understood as the womb or genitals; Frymer-Kensky and the critical commentaries discuss the ordeal at length. The word itself is well understood; scholarly discussion concerns the precise anatomical referent of the euphemism and the meaning of the oath gesture, not the sense of the word.
Sources
HALOT, s.v. ירךlexicon
BDB, s.v. ירךlexicon
DCH, s.v. ירךlexicon
G. Mayer, "ירך", in Theological Dictionary of the Old Testament (TDOT)dictionary
TWOT, s.v. ירךdictionary
Tikva Frymer-Kensky, "The Strange Case of the Suspected Sotah (Numbers V 11-31)", Vetus Testamentum 34 (1984)article