In general, to act in a way which results in an object becoming completely permeated or impregnated by some quality.
To wet or stain an object completely with some physical quality.
To temper an action or decision.
To add a leavening agent.
To cause to rise by fermentation.
To imbue; to infect; to vitiate.
To rise or become larger.
Anything that induces change, especially a corrupting or vitiating change.
Any agent used to make dough rise or to have a similar effect on baked goods.