Third order

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, the male religious: for example Franciscans, Dominicans, Carmelite and Augustinian friars), or its "second order" (contemplative female religious associated with the "first order"). Members of third orders, known as tertiaries (Latin tertiarii, from tertius, third), may be lay men and women or ordained men (or women, if the tradition ordains them) who do not take religious vows, but participate in the good works of order and may be allowed to wear at least some elements of the order's habit, such as a scapular. Less often, they belong to a religious institute (a "congregation") that is called a "third order regular".

Roman Catholic canon law states:

The old monastic orders had attached to their abbeys confraternities of lay men and women, going back in some cases to the 8th century. The Confraternity Book of Durham is extant and embraces some 20,000 names in the course of eight centuries. Emperors and kings and the most illustrious men in church and state were commonly confraters of one or other of the great Benedictine abbeys. The confraters and consorors were made partakers in all the religious exercises and other good works of the community to which they were affiliated, and they were expected in return to protect and forward its interests; but they were not called upon to follow any special rule of life.

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