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

Recent Examples on the Web
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.
Chiang’s team used a liquid reagent made of water and ammonium fluoride — the active chemical in glass etchant — to do the exact opposite. — Mrigakshi Dixit, Interesting Engineering, 28 May 2026 There are a number of products on the market that contain essential oils, like clove or citrus, sodium or ammonium derivatives or even acetic acid (vinegar). — Dawn Pettinelli, Hartford Courant, 13 June 2026 For example, adding too much fertilizer with ammonium, or NH4, can result in the soil becoming too acidic over time. — Rae Ford, Martha Stewart, 7 June 2026 The mineral, known as struvite, is a crystalline, colorless ammonium magnesium phosphate that has long been known for its flame-retardant qualities. — Ben Coxworth march 20, New Atlas, 20 Mar. 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 7 Jul. 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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