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onium

adjective oni·um \ ˈō-nē-əm \

Definition of onium

: being or characterized by a usually complex cation

Origin and Etymology of onium

-onium

-onium

noun suffix

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

adjective oni·um \ ˈō-nē-əm \

medical Definition of onium

: being or characterized by a usually complex cation
  • onium salts

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