Greek word · G2219

ζύμη

zymē

leaven

Leaven in the ancient sense: a piece of fermented dough held back from the last baking and worked into fresh flour and water to make it rise. It is not a fixed symbol. In context it can be negative (corruption, a hidden bad influence) or positive (the kingdom spreading, Matt 13:33).

Appears 13 times in 11 verses of the Greek New Testament. · Updated October 31, 2026

What it means

ζύμη, -ης, ἡ

[in LXX for חָמֵץ, Exodus 12:16 13:3 23:18 34:25, Deuteronomy 16:3; שְׂאֹר, Exodus 12:16, 19 13:7, Leviticus 2:11, Deuteronomy 16:4 * ;]

leaven: Matthew 13:33, Luke 13:21; τ. ἄρτου, Matthew 16:12. Metaphorical, of a moral influence or tendency, always, exc. in the Parable of the Leaven (Matthew 13:33, Luke 13:21), for evil: 1 Corinthians 5:6-8, Galatians 5:9; ζ. τ. Φαρισαίων, Matthew 16:6, 11, Mark 8:16, Luke 12:1 (Cremer, 723).†

(AS)

From G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), via STEPBible.org (CC BY 4.0).

In depth

From the study of Matthew 16:6

Range of meaning: Leaven in the ancient sense: a piece of fermented dough held back from the last baking and worked into fresh flour and water to make it rise. By extension it was a picture of any small active influence that spreads quietly until it affects the whole thing ('a little leaven leavens the whole lump', Gal 5:9; 1 Cor 5:6). It is not a fixed symbol. In context it can be negative (corruption, a hidden bad influence) or positive (the kingdom spreading, Matt 13:33).
Against the English: KJV, BSB, ESV, NASB and YLT say 'leaven'. NIV, NLT and WEB say 'yeast'. 'Yeast' is understandable, but modern readers picture packets of dried yeast. They lose the idea of old dough carried over from batch to batch, which is the part that made the image work.
How it drifted: Commercial yeast arrived in the 19th–20th centuries and replaced sourdough leaven in everyday kitchens, so 'yeast' became the natural modern word. Meanwhile 'leaven' dropped out of ordinary speech.
Used elsewhere in the period: In the Hebrew Bible, leaven (Hebrew se'or, and chamets for leavened food) had to be cleared out of the house for Passover and Unleavened Bread (Exod 12:15–20; 13:7). It was barred from offerings burned on the altar (Lev 2:11). Yet leavened loaves were offered with the thank offering (Lev 7:13) and at the Feast of Weeks (Lev 23:17). Philo treats leaven as a picture of being 'puffed up' or arrogant (Special Laws 1.293). Plutarch (Roman Questions 109) calls leaven 'itself the product of corruption' that 'corrupts the dough'. A later rabbinic prayer uses 'the leaven in the dough' for the evil inclination (b. Berakhot 17a). Paul uses it for a corrupting influence inside the community (1 Cor 5:6–8; Gal 5:9).

From the study of 1 Corinthians 5:7

Range of meaning: Leaven: a piece of fermented, soured dough kept back from a previous batch and worked into new flour to make it rise. By extension, anything small that quietly spreads through and changes a whole mass. As a figure it can be bad (corruption, false teaching, hypocrisy: Mark 8:15; Matt 16:6–12; Gal 5:9) or good (the kingdom spreading through the world: Matt 13:33).
Against the English: KJV, ESV, NASB and BSB say 'leaven'; NIV, NLT and WEB say 'yeast.' 'Yeast' makes modern readers think of dried granules from a packet, a clean starting ingredient. It loses the point that ancient leaven was old dough, kept alive by carrying part of each batch into the next one. That is why Paul can call it 'old' leaven.
How it drifted: Commercial yeast changed baking in the 1800s, and 'yeast' became the everyday word, so the picture of a sourdough chain running from batch to batch dropped out of most readers' minds.
Used elsewhere in the period: Exod 12:15–20 and 13:7 require all leaven (Hebrew seʾor, the starter, and ḥametz, leavened food) to be removed from Israelite houses for the seven days of Unleavened Bread. Mishnah Pesaḥim 1:1–4 describes searching the house by lamplight on the night before Passover and then burning the leaven. Leaven was banned from most altar offerings (Lev 2:11) but was required in some, such as the thank-offering bread (Lev 7:13) and the two loaves of Weeks (Lev 23:17). Plutarch (Roman Questions 109) says leaven is itself produced by corruption and corrupts the dough it is mixed with. Philo reads leaven as a symbol of being 'puffed up' (Special Laws 1.293; 2.184–85). Later rabbinic sources call the evil impulse 'the leaven in the dough' (b. Berakhot 17a).

From the study of 1 Corinthians 5:8

Range of meaning: Leaven: a piece of fermented dough kept back from an earlier batch and kneaded into new dough so it rises. By extension, anything that quietly permeates and changes a whole, often with the sense of corruption or decay.
Against the English: KJV, NASB and ESV have 'leaven'. WEB has 'yeast', and the NIV uses 'yeast' in verses 6–7. 'Yeast' is not wrong, but modern readers think of a clean packet of dried cultured yeast. The ancient image was old, souring dough carried over from batch to batch. That is why it can be called 'old' and why a little of it 'leavens the whole lump' (5:6).
How it drifted: Commercial baker's yeast, isolated and sold separately from dough, belongs to the modern period. Translations that say 'yeast' lose the picture of old, spreading fermentation that Paul's argument depends on.
Used elsewhere in the period: Exodus 12:15, 19 and 13:7 require all leaven to be removed from Israelite houses for the seven days of Unleavened Bread. Leviticus 2:11 bars leaven from offerings burnt on the altar. The Mishnah (Pesahim 1:1, written down around 200 AD but reflecting earlier practice) describes searching the house for leaven by lamplight on the night before Passover. Plutarch (Roman Questions 109), writing around 100 AD, says leaven 'is itself the product of corruption and corrupts the dough'. Philo treats leaven's rising as a picture of pride puffing itself up (Special Laws 1.293; Questions on Exodus 1.15). Jesus warns against 'the leaven of the Pharisees' (Mark 8:15), and Paul quotes the same proverb in Galatians 5:9.

Where it appears

Matthew · 4

Matthew 13:33 ζύμῃ, to leaven,

He told them still another parable: “The kingdom of heaven is like leaven that a woman took and mixed into three measures of flour, until all of it was leavened.”

Here: Leaven: a lump of old, soured, fermenting dough kept back from the last baking and worked into new dough. It is small and unimpressive, and Jews often linked it with corruption, yet it is powerful enough to transform the whole batch.
Matthew 16:6 ζύμης leaven

“Watch out!” Jesus told them. “Beware of the leaven of the Pharisees and Sadducees.”

Here: A lump of old fermented dough saved from an earlier batch and kneaded into new dough so that it rises. The picture is a small hidden thing that slowly works through the whole. Matthew 16:12 says it stands for the 'teaching' of these groups.
Matthew 16:11 ζύμης leaven

How do you not understand that I was not telling you about bread? But beware of the leaven of the Pharisees and Sadducees.”
Matthew 16:12 ζύμης leaven

Then they understood that He was not telling them to beware of the leaven used in bread, but of the teaching of the Pharisees and Sadducees.

Here: Fermented starter dough: a lump held back from an earlier batch and kneaded into new dough, where it spreads through the whole batch and changes it. The disciples took it literally. They now see it as a picture.

Mark · 2

Mark 8:15 ζύμης ζύμης leaven

“Watch out!” He cautioned them. “Beware of the leaven of the Pharisees and of Herod.”

Here: A lump of old fermented dough kept back and worked into a new batch, which then rises all the way through. It is a picture of a small thing that spreads and changes everything it touches. The disciples hear it as literal bread (v.16).

Luke · 2

Luke 12:1 ζύμης leaven

In the meantime, a crowd of many thousands had gathered, so that they were trampling one another. Jesus began to speak first to His disciples: “Beware of the leaven of the Pharisees, which is hypocrisy.

Here: A lump of old, fermented dough kept back and kneaded into a new batch, which it slowly and invisibly works through. A small, hidden influence that spreads through everything.
Luke 13:21 ζύμῃ to leaven

It is like leaven that a woman took and mixed into three measures of flour, until all of it was leavened.”

1 Corinthians · 4

1 Corinthians 5:6 ζύμη leaven

Your boasting is not good. Do you not know that a little leaven works through the whole batch of dough?

Here: Leaven: a lump of old, fermented dough kept back from an earlier batch and worked into new flour. Not packaged yeast. It prepares for verse 7's 'old leaven' and the Passover clear-out.
1 Corinthians 5:7 ζύμην, leaven,

Get rid of the old leaven, that you may be a new unleavened batch, as you really are. For Christ, our Passover lamb, has been sacrificed.

Here: Fermenting dough used to raise new dough. Here it stands for the corrupting presence the church is tolerating: the man in verses 1–2 and the community's puffed-up pride about it, which spreads through everyone.
1 Corinthians 5:8 ζύμῃ ζύμῃ leaven

Therefore let us keep the feast, not with the old bread, leavened with malice and wickedness, but with the unleavened bread of sincerity and of truth.

Here: Sourdough starter: a lump of old fermented dough kept back from an earlier batch and worked into new dough. Every Israelite household had to clear it out before Passover. Here it stands for corruption that spreads.

Galatians · 1

Galatians 5:9 ζύμη leaven

A little leaven works through the whole batch of dough.

Here: A bit of old fermented dough kept back from an earlier batch and worked into new dough to make it rise. In context it is the small foreign element now at work among the Galatians: the agitators and their demand for circumcision.

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