onium

1 of 2

adjective

oni·​um ˈō-nē-əm How to pronounce onium (audio)
: being or characterized by a usually complex cation

-onium

2 of 2

noun suffix

: an ion having a positive charge
hydronium
compare -ium sense 1b

Word History

Etymology

Adjective

-onium

Noun suffix

New Latin, from ammonium

First Known Use

Adjective

1905, in the meaning defined above

Time Traveler
The first known use of onium was in 1905

Dictionary Entries Near onium

on it

onium

-onium

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Cite this Entry

“Onium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/onium. Accessed 6 Dec. 2023.

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Medical Definition

onium

adjective
oni·​um ˈō-nē-əm How to pronounce onium (audio)
: being or characterized by a usually complex cation
onium salts
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