Translation of "third order" into Welsh

In relation to religious orders, a third order is an association of persons who live according to the ideals and spirit of a Catholic, Anglican, or Lutheran religious order, but do not belong to its "first order" (generally, in the Catholic Church, Franciscans, Dominicans, Carmelite and Augustinian friars), or its "second order" (contemplative nuns associated with the "first order").