Other forms: nuns
A nun is a woman who's dedicated her life to religious observance. Most nuns spend their time praying or meditating and doing service work in their communities.
You may picture a Catholic nun when you hear the word nun, but there are nuns of other faiths as well, including Hindus, Lutherans, Jains, and Buddhists. Nuns serve the poor and hungry, sometimes running schools or orphanages, and they have in common a strict dedication to religion. Nun comes from the Old English nunne, and the Late Latin nonna, "nun," originally a generic word for addressing an older person.