An oxide with each molecule containing one oxygen atom. (noun)
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.
Use "monoxide" in a sentence
"And I also proved that carbon monoxide is not deadly by sitting in a running vehicle for an hour."
"I dunno that that's so -- carbon monoxide is almost exactly the same density as air, and the National Fire Protection Association code is fine with putting a detector on the ceiling so long as it's someplace you can hear it."
"Carbon monoxide is a natural component of the atmosphere as well."