Definition of onium
: being or characterized by a usually complex cation
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Origin and Etymology of onium
-onium
First Known Use: 1905
-onium
noun suffix
oni·um
Definition of -onium
: an ion having a positive charge hydronium — compare -ium 1b
Origin and Etymology of -onium
New Latin, from ammonium
Medical Dictionary
onium
play
adjective
oni·um
\ˈō-nē-əm\
Medical Definition of onium
: being or characterized by a usually complex cation onium salts
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