monk

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A man who is a member of a brotherhood living in a monastery and devoted to a discipline prescribed by his order.

from The Century Dictionary.

• noun Originally, a man who retired from the world for religious meditation and the practice of religious duties in solitude; a religious hermit; in later use, a member of a community or fraternity of men formed for the practice of religious devotions and duties, and bound by the vows of poverty, celibacy, and obedience to a superior; specifically, a regular male denizen of a monastery.
• noun A name of various animals.
• noun In printing, an over-inked spot or blotch in print, usually made by imperfect distribution of ink. Compare friar, 2.
• noun Milit., a fuse for firing mines.
• noun Synonyms Hermit, etc. See anchoret.

from the GNU version of the Collaborative International Dictionary of English.

• noun A man who retires from the ordinary temporal concerns of the world, and devotes himself to religion; one of a religious community of men inhabiting a monastery, and bound by vows to a life of chastity, obedience, and poverty.
• noun (Print.) A blotch or spot of ink on a printed page, caused by the ink not being properly distributed. It is distinguished from a friar, or white spot caused by a deficiency of ink.
• noun A piece of tinder made of agaric, used in firing the powder hose or train of a mine.
• noun A South American monkey (Pithecia monachus); also applied to other species, as Cebus xanthocephalus.
• noun The European bullfinch.
• noun (Zoöl.) a South American and West Indian bat (Molossus nasutus); -- so called because the males live in communities by themselves.
• noun (Zoöl.) the friar bird.
• noun (Zoöl.) a species of seal (Monachus albiventer) inhabiting the Black Sea, the Mediterranean Sea, and the adjacent parts of the Atlantic.
• noun (Bot.) a kind of dock; -- also called patience (Rumex Patientia).

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A male member of a monastic order who has devoted his life for religious service.
• noun in earlier usage, an eremite or hermit devoted to solitude, as opposed to a cenobite, who lived communally.
• noun slang A male who leads an isolated life; a loner, a hermit.
• noun slang An unmarried man who does not have sexual relationships.
• noun slang A judge.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a male religious living in a cloister and devoting himself to contemplation and prayer and work
• noun United States jazz pianist who was one of the founders of the bebop style (1917-1982)