[ mon-ad, moh-nad ]
/ ˈmɒn æd, ˈmoʊ næd /
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  1. any simple, single-celled organism.
  2. any of various small, flagellate, colorless ameboids with one to three flagella, especially of the genus Monas.
Chemistry. an element, atom, or group having a valence of one.Compare dyad (def. 3), triad (def. 2a).
  1. (in the metaphysics of Leibniz) an unextended, indivisible, and indestructible entity that is the basic or ultimate constituent of the universe and a microcosm of it.
  2. (in the philosophy of Giordano Bruno) a basic and irreducible metaphysical unit that is spatially and psychically individuated.
  3. any basic metaphysical entity, especially having an autonomous life.
a single unit or entity.



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Origin of monad

First recorded in 1605–15; from Late Latin monad- (stem of monas), from Greek monás (stem monád- ) “unity, monad”; see mon-, -ad1
mo·nad·ic [muh-nad-ik], /məˈnæd ɪk/, mo·nad·i·cal, mo·nad·al, adjectivemo·nad·i·cal·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for monad

/ (ˈmɒnæd, ˈməʊ-) /


plural -ads or -ades (-əˌdiːz) philosophy
  1. any fundamental singular metaphysical entity, esp if autonomous
  2. (in the metaphysics of Leibnitz) a simple indestructible nonspatial element regarded as the unit of which reality consists
  3. (in the pantheistic philosophy of Giordano Bruno) a fundamental metaphysical unit that is spatially extended and psychically aware
a single-celled organism, esp a flagellate protozoan
an atom, ion, or radical with a valency of one
Also called (for senses 1, 2): monas
monadical, adjectivemonadically, adverb
C17: from Late Latin monas, from Greek: unit, from monos alone
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for monad

[ mōnăd′ ]


An atom or a radical with a valence of 1.
A single-celled microorganism, especially a protozoan of the genus Monas.
Any of the four chromatids of a tetrad that, after the first and second meiotic divisions, separate to become the chromosomal material in each of the four daughter cells.
mo•nadic (mə-nădik) null adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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