Holy Leaven

Okay, so you know how when you make a cake, you mix together ingredients like flour, sugar, eggs, and baking powder to make a yummy dessert? Well, when people make a special bread called "holy bread" or "prosphora" in some religious ceremonies, they add something called "holy leaven" to the mix.

"Leaven" is just another word for yeast, which is a tiny living thing that helps bread dough rise and get nice and fluffy. But "holy leaven" is special because it's been blessed by a religious leader, like a priest or a bishop, who prays over the yeast and asks God to bless it.

This special yeast is then kept around (kind of like a sourdough starter) so that whenever someone wants to make holy bread, they can use a bit of the blessed yeast from before rather than starting from scratch. This way, each new batch of holy bread is connected to all the ones that came before it and symbolizes the continuation of the faith over time.

So in summary, holy leaven is yeast that has been blessed by a religious leader and is used to make a special kind of bread that has a lot of meaning in certain religious ceremonies.