ζύμης [6 verses](noun sg fem gen)"Leaven" is sometimes translated as "yeast." It is from the Greek zyme, which means any kind of bread or beer "yeast." It is from a root word meaning "to mix." This was a time when yeast didn't come in little packets but was maintained as a live culture, in this case, in the raw bread dough itself.  - "Leaven" means "yeast," the culture that spreads through flour to create the "bubbles" that make bread rise.  Leaven produces gas, that is, a type of breath. The Greek word, "breath," also means "spirit." Breath produces words. Words capture ideas. It is Jesus's symbol for ideas that propagate themselves. Jesus compares the kingdom of heaven to leaven as well and the ideas of the Pharisees.