Definition of "monatomic" [mon•a•tom•ic]

• Occurring as single atoms: Helium is a monatomic gas. (adjective)
• Having one replaceable atom or radical. (adjective)
• Univalent. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Ionization was also observed in monatomic inert gases, which proves that the unit of electric charge is a constituent of the atom that is liberated from it by ionization."
• "Due to their antisocial and imperturbable nature they occur in ChemicalData as only their monatomic selves."
• "These atoms still try to reshape even after forming a molecule but find their efforts opposed by the new covalent bond, the covalent bond gets broken by this reshaping force when the molecule moves to a spatial position where the Casimir force changes sufficiently that the reshaping force disassociates the molecule restoring monatomic energy levels."