1. A substance used to produce fermentation in dough or a liquid
   "Yeast is a common leavening agent used in bread making";
   - leaven
    
2. An influence that works subtly to lighten or modify something
   "his sermons benefited from a leavening of humour";
   - leaven

1. Cause to puff up with a leaven
   "The yeast leavened the bread dough";
   - raise, prove

Derived forms: leavenings

Type of: bring up, elevate, get up, imponderable, lift, raise

Encyclopedia: Leavening, North Yorkshire