1
: a substance (such as yeast) that makes dough rise and become light before it is baked
called also leavening
2
literary
: something that makes a situation or mood less serious
a serious book that includes a few humorous stories as leaven
leavens; leavened; leavening
1
formal
: to make (something) less serious and often more exciting
Her jokes leavened [=lightened] the meeting's mood.
He needs to leaven his speeches with more humor.
2
: to add leaven to (bread, dough, etc.)
using yeast to leaven the dough/bread
Some breads are leavened [=made with leaven] and some breads are unleavened.
Cite this Entry
“Leaven.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/leaven. Accessed 17 Apr. 2026.
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