Hebrew word · H6363

פֶּ֫טֶר

peter

firstborn

From the verb patar, 'to split open, set free, let loose' (1 Kgs 6:18, 'open flowers'; Prov 17:14, letting out water). The noun means 'that which opens'. In the phrase peter rechem it means the offspring that first breaks open a womb.

Appears 12 times in 10 verses of the Hebrew Old Testament. · Updated November 01, 2026

What it means

firstborn, firstling, that which separates or first opens

Also means: pit.rah (פִּטְרָה "firstborn" H6363B)

Abridged from Brown, Driver and Briggs, A Hebrew and English Lexicon of the Old Testament (1906), via STEPBible.org (CC BY 4.0).

In depth

From the study of Exodus 13:2

Range of meaning: From the verb patar, 'to split open, set free, let loose' (1 Kgs 6:18, 'open flowers'; Prov 17:14, letting out water). The noun means 'that which opens'. In the phrase peter rechem it means the offspring that first breaks open a womb.
Against the English: KJV and WEB, 'whatsoever/whatever openeth the womb', keep the vivid picture. BSB has 'the firstborn from every womb' and NIV 'the first offspring of every womb'. These are clear, but they flatten the image of opening and lose the sense that this phrase is a definition.
Used elsewhere in the period: Also in Exod 13:12, 15; 34:19; Num 3:12; 18:15. The Greek Septuagint renders it dianoigon mētran, 'opening the womb', and Luke 2:23 echoes this when Jesus is presented at the temple. Later Jewish law (Mishnah, tractate Bekhorot 8) drew conclusions from the phrase. One example: a child born by surgical delivery does not count, because he did not 'open the womb'.

From the study of Numbers 8:16

Range of meaning: The root p-ṭ-r means 'to separate, set free, let out, open' (compare 1 Sam 19:10, 'slipped away'; Prov 17:14, 'letting out' water). The noun peter / pitrah means 'that which opens' or 'that which first breaks out'. With rechem ('womb') it is a fixed phrase for a mother's first child.
Against the English: KJV 'such as open every womb' and WEB 'all who open the womb' keep the physical image. BSB 'all who come first from the womb' keeps the sense but softens the picture. Some modern versions flatten it to 'firstborn sons', which loses the definition by the mother.
Used elsewhere in the period: Peter rechem is the standard phrase of the firstborn laws: Exod 13:2, 12, 15; 34:19; Num 3:12; 18:15. The feminine form pitrah appears only here in the Hebrew Bible.

From the study of Exodus 13:12

Range of meaning: It comes from the root patar, 'to split open, release, let go free'. The same root is used of David slipping away (1 Sam 19:10), of flowers opening (1 Kgs 6:18, 29), and of letting water out (Prov 17:14). The noun peter means 'that which breaks open'. It is almost always joined to 'womb' (peter rechem) and means a mother's first offspring (Exod 13:2, 12, 15; 34:19–20; Num 3:12; 18:15; Ezek 20:26).
Against the English: Most English versions use 'firstborn'. To modern ears that means 'eldest child of the family', and in Israelite law the father's eldest son was the heir with a double share (bekhor, Deut 21:15–17). Peter rechem is a different test. It is the first to open a particular mother's womb. KJV/WEB 'all that openeth the womb/matrix' and ESV 'first opens the womb' keep this. BSB's 'firstborn male of every womb' keeps the womb but loses the picture of opening.
How it drifted: Translators merged peter rechem with bekhor ('firstborn'), the inheritance word in v. 13. In the text the two overlap but are not the same category.
Used elsewhere in the period: Later rabbinic law worked out the difference. Mishnah Bekhorot 8:1 discusses a son who is a 'firstborn for inheritance but not for the priest' and the reverse. One example is a child born after the mother had a miscarriage, because the womb had already been 'opened'. Another is a child delivered by caesarean section, who did not 'open the womb'. Luke 2:23 quotes the phrase in Greek: pan arsen dianoigon mētran, 'every male that opens the womb'.

Where it appears

Exodus · 8

Exodus 13:2 פֶּ֤טֶר [the] firstborn of

“Consecrate to Me every firstborn male. The firstborn from every womb among the Israelites belongs to Me, both of man and beast.”

Here: Literally 'the opening', meaning the one who first breaks open a womb. It stands next to 'firstborn' and defines it: the firstborn here is counted from the mother.
Exodus 13:12 פֶּֽטֶר־ פֶּ֣טֶר׀ firstborn of

you are to present to the LORD the firstborn male of every womb. All the firstborn males of your livestock belong to the LORD.

Here: Literally 'the opening of': the first offspring to break open the womb. The person is defined by what happens at birth, not by inheritance rank.
Exodus 13:13 פֶּ֤טֶר firstborn of

You must redeem every firstborn donkey with a lamb, and if you do not redeem it, you are to break its neck. And every firstborn of your sons you must redeem.
Exodus 13:15 פֶּ֤טֶר firstborn of

And when Pharaoh stubbornly refused to let us go, the LORD killed every firstborn in the land of Egypt, both of man and beast. This is why I sacrifice to the LORD the firstborn male of every womb, but I redeem all the firstborn of my sons.’
Exodus 34:19 פֶּ֥טֶר פֶּ֖טֶר firstborn of, [the] firstborn of

The first offspring of every womb belongs to Me, including all the firstborn males among your livestock, whether cattle or sheep.
Exodus 34:20 וּפֶ֤טֶר and [the] firstborn of

You must redeem the firstborn of a donkey with a lamb; but if you do not redeem it, you are to break its neck. You must redeem all the firstborn of your sons. No one shall appear before Me empty-handed.

Here: From a root meaning "to split open" or "let out." It picks up v.19's "every opener of the womb is mine": the animal that came out first, opening its mother's womb. With the 'and' it moves from cattle and sheep, which can be sacrificed, to a case that needs separate handling.

Numbers · 3

Numbers 3:12 פֶּ֥טֶר [the] firstborn of

“Behold, I have taken the Levites from among the children of Israel in place of every firstborn Israelite from the womb. The Levites belong to Me,
Numbers 8:16 פִּטְרַ֨ת [the] firstborn of

For the Levites have been wholly given to Me from among the sons of Israel. I have taken them for Myself in place of all who come first from the womb, the firstborn of all the sons of Israel.

Here: 'The opening of', meaning what first breaks open the womb. This feminine form occurs only here. Elsewhere the Bible uses the shorter form peter (Exod 13:2, 12).
Numbers 18:15 פֶּ֣טֶר firstborn of

The firstborn of every womb, whether man or beast, that is offered to the LORD belongs to you. But you must surely redeem every firstborn son and every firstborn male of unclean animals.

Here: Literally 'opener', the one who breaks through first. It defines the firstborn physically, from the mother's side, rather than by family rank.

Ezekiel · 1

Ezekiel 20:26 פֶּ֣טֶר firstborn of

And I pronounced them unclean through their gifts—the sacrifice of every firstborn in the fire—so that I might devastate them, in order that they would know that I am the LORD.

Here: Literally 'the opening'. Together with the next word it is a fixed phrase for the firstborn child or animal. The phrase belongs to the law language of Exodus, and Ezekiel's hearers would have recognised it.

Word data: STEPBible.org (CC BY 4.0), main text only.