NUN (O. Eng. nunnc, from Lat. nonnus, nonna, familiar terms for an old man or woman), a member of a community of women, living under vows a life of religious observance (see MONASTJCTSM) . In ecclesiastical Latin nonnus was used by the younger members of a religious community for their elders, and so, in the regula of St Benedict, cap. 62, Juniores aulem Priores suos nonnos vacant quod inlelligitur paterna reverentia (Du Cange, Glossarium, s.v. nonnus). While nonna has remained as the generic name of a female religious, nonnus has been replaced by monachus and its various derivatives (see MONK) .
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)