le v@n
noun
1. a substance, such as yeast, that produces fermentation in a dough or batter and causes it to rise.
2. an element that has a subtle, enlivening, or modifying effect; leavening.
the leaven of humor
transitive verb
1. to produce fermentation in.
The dough is leavened with yeast.
2. to enliven or change with a subtle, pervasive influence.
The story is leavened by her sense of comic irony.