First Known Use: 1905
Dictionary
onium
adjective oni·um \ˈō-nē-əm\
Definition of ONIUM
: being or characterized by a usually complex cation
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Origin of ONIUM
-onium
Medical Dictionary
onium
adjective oni·um \ˈō-nē-əm\
Medical Definition of ONIUM
: being or characterized by a usually complex cation <onium salts>
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