Pesach is a Hebrew word that means "pass over" or "skip over". The name comes from the biblical story of the Exodus, in which God passed over the homes of the Israelites during the tenth plague in Egypt, while the firstborn sons of the Egyptians were killed.
The Israelites were instructed to mark their doorposts with the blood of a lamb, so that God would know to pass over their homes. This event is commemorated during the Pesach holiday, which celebrates the Israelites' liberation from slavery in Egypt and their journey to freedom.