Definition of "leaven" in English

noun

1. Any agent used to make dough rise or to have a similar effect on baked goods.

2. (figurative) Anything that induces change, especially a corrupting or vitiating change.

3. Chametz.

verb

1. (transitive) To add a leavening agent.

   • Yeast is used to leaven bread, making it rise during baking.

2. (transitive) To cause to rise by fermentation.

3. (transitive, figuratively) To temper an action, decision, attitude, characteristic, etc.

4. (transitive, figuratively) To imbue; to infect; to vitiate.

   • The comedian's jokes helped leaven the atmosphere during the serious meeting.
   • Her optimism seemed to leaven the otherwise tense environment.

5. To rise or become larger; to prove.