The univalent chemical ion NH4+, derived from ammonia, whose compounds chemically resemble the alkali metals. (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 "ammonium" in a sentence
"A year later Ampère discovered that nitrogen and hydrogen, when combined in certain proportions to form what he called ammonium, have the same property."
"ANFO seemed to be an acronym for ammonium nitrate and fuel oil."
"The oxidizer is called ammonium dinitramide A.D.N."