(seed-DOER) n. Siddur. Prayer book. Arrangement of the book begins with Shacharit, Minchah, and Ma‘ariv services, then Shabbat and festival services. A Machzor is a prayerbook used for holiday services.
a book outlining the liturgy of religious services
(formally, "Book of Common Prayer" - A book containing the authorized forms of services and for the administration of the sacrament; the first Prayer Book was published in 1549, and the most recent were published in 1928 (USA) and 1962 (Canada).