Identify the principal services, books and terms named by Orthodox sources. This page starts with that question because it is the most useful way into the subject. It names the visible structure, keeps the vocabulary plain and points to the source trail instead of asking the reader to accept an unexplained conclusion.
The useful distinction here is between a named form and a local order of service. Books, offices and terms describe a tradition, while the exact sequence belongs to the community and calendar that are celebrating. The Feast & Form Index gives this explanation a place among related records: feast, season, office, object or visual cue. That arrangement lets a reader arrive through ordinary language and leave with a more precise term.
The editorial boundary is deliberate. We do not assign a current schedule, repeat private contact details, or turn a local custom into a universal rule. When the evidence is limited, the page says so and offers a nearby source, such as the source register or the method note.
Orthodox sources name the Divine Liturgy as the principal Sunday service, with Vespers and Matins marking the hours around it, and the books that carry these services, such as the Horologion, the Psalter, and the Octoechos, are worth knowing by name. Readers who want to see how another tradition orders its own Sunday hour, and how preaching and the Lord's Supper relate within it, can find a Sunday gathering explained in plain terms. The terms differ, yet both describe a community that gathers to hear Scripture read and to keep a weekly rhythm of prayer.
