rosary, Religious exercise in which prayers are recited and counted on a string of beads or knotted cord, which is also called a rosary. Many of these devices are highly ornamental and incorporate jewels. The practice of using a rosary or “counting beads” occurs widely in world religions, including Christianity, Hinduism, Buddhism, and Islam. In Christianity, the most common rosary is that of the Virgin Mary. Its origin is uncertain, but it is associated with St. Dominic and reached its definitive form in the 15th century.