[ mon-uh-tom-ik ]
/ ˌmɒn əˈtɒm ɪk /

adjective Chemistry.

having one atom in the molecule.
containing one replaceable atom or group.
having a valence of one.

Origin of monatomic

First recorded in 1840–50; mon- + atomic

Related forms

mon·a·tom·i·cal·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for monatomic

British Dictionary definitions for monatomic


monoatomic (ˌmɒnəʊəˈtɒmɪk)

/ (ˌmɒnəˈtɒmɪk) /

adjective chem

(of an element) having or consisting of single atomsargon is a monatomic gas
(of a compound or molecule) having only one atom or group that can be replaced in a chemical reaction
a less common word for monovalent
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

Medicine definitions for monatomic


[ mŏn′ə-tŏmĭk ]


Occurring as single atoms.
Having one replaceable atom or radical.

Related forms

mon′a•tomic•al•ly adv.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.