The Order of Preachers (Latin: Ordo Praedicatorum), after the 15th century more commonly known as the Dominican Order or Dominicans, is a Roman Catholic religious order founded by Saint Dominic and approved by Pope Honorius III (1216–27) on 22 December 1216 in France. Membership in the Order includes friars, nuns, congregations of active sisters, and lay persons affiliated with the order (formerly known as tertiaries, now Lay or Secular Dominicans).
A number of other names have been used to refer to both the order and its members.
Members of the order generally carry the letters O.P. standing for Ordinis Praedicatorum, meaning of the Order of Preachers, after their names.
Founded to preach the Gospel and to combat heresy, the order is famed for its intellectual tradition, having produced many leading theologians and philosophers. The Dominican Order is headed by the Master of the Order, who is currently Father Bruno Cadoré.
Like his contemporary, Francis of Assisi, Dominic saw the need for a new type of organization, and the quick growth of the Dominicans and Franciscans during their first century of existence confirms that the orders of mendicant friars met a need.