Tertiaries
a name given by Church writers to a class in the Roman Catholic Church who, without entering into the seclusion of a monastery, aspire to practise in ordinary life all the substantial obligations of the scheme of virtue laid down in the Gospel. It was under St. Francis and the mendicant orders generally that the institute of Tertiaries reached its full development. Similar lay associations were organized in connection with the Dominican, Carmelite, and Augustinian, as well as with certain of the more modern orders; and a brotherhood of the same character had already been formed by the Templars.
The institute of Tertiaries, properly so called, is quite distinct from that of the lay " "co "confraternities" which exist in connection with the several orders, and the objects of which are very similar.