Chametz refers to any food product made from the five grains: wheat, barley, rye, oats, and spelt, that has leavened or fermented. During the Jewish holiday of Passover, it is forbidden to consume or possess chametz, as the holiday commemorates the Exodus from Egypt when the Israelites left in haste, not allowing their bread to rise. To prepare for Passover, Jewish families thoroughly clean their homes to remove any traces of chametz. This practice symbolizes spiritual cleansing and renewal. Instead of chametz, they eat matzah, an unleavened bread, which serves as a reminder of their ancestors' quick departure from slavery.