Liturgy comes from the Greek leitourgia — literally "public work" or "service of the people." It refers to the formal, structured order of religious worship — the prescribed texts, prayers, rituals, and ceremonies that define how a community practices its faith collectively.
In the Jewish context, the most obvious example is the Haggadah — the text you follow at the Seder. It is liturgy: a fixed order (seder literally means "order") of prayers, blessings, songs, questions, and narrative that structures the collective religious act of remembering the Exodus.
