ammonium

noun

am·​mo·​ni·​um ə-ˈmō-nē-əm How to pronounce ammonium (audio)
: an ion NH4+ derived from ammonia by combination with a hydrogen ion and known in compounds (such as salts) that resemble in properties the compounds of the alkali metals

Examples of ammonium in a Sentence

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Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
To fix the chemical interference, the research team added a decoupling modulator molecule featuring ammonium ions, iodide ions, and two sulfonate groups to the precursor solution. — Mrigakshi Dixit, Interesting Engineering, 26 Oct. 2026 The test strips for chlorine and quaternary ammonium expired in 2025. — Arkansas Online, 26 Oct. 2026 The brand’s Daily Nourish Body Lotion keeps things refreshingly simple, pairing 12% ammonium lactate with moisturizing glycerin, mineral oil, and not much else. — Christa Joanna Lee, Allure, 21 Oct. 2026 Quaternary ammonium compounds can also accumulate in the testicles, Hrubec said. — Sandee Lamotte, CNN Money, 7 Aug. 2026 See All Example Sentences for ammonium

Word History

Etymology

New Latin, from ammonia

First Known Use

1808, in the meaning defined above

Time Traveler
The first known use of ammonium was in 1808

Phrases Containing ammonium

Rhymes for ammonium

See All Rhymes for ammonium

Browse Nearby Words

Ammonitoidea
ammonium
ammonium bicarbonate
See all Nearby Words

Cite this Entry

“Ammonium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ammonium. Accessed 30 Oct. 2026.

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Kids Definition

ammonium

noun
am·​mo·​ni·​um ə-ˈmō-nē-əm How to pronounce ammonium (audio)
: an ion that comes from the combination of ammonia with a hydrogen ion

Medical Definition

ammonium

noun
am·​mo·​ni·​um ə-ˈmō-nē-əm How to pronounce ammonium (audio)
: an ion NH4+ derived from ammonia by combination with a hydrogen ion and known in organic compounds (as quaternary ammonium compounds) and in compounds (as salts) that resemble in properties the compounds of the alkali metals
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