onium

adjective
oni·​um | \ ˈō-nē-əm How to pronounce onium (audio) \

Definition of onium

 (Entry 1 of 2)

: being or characterized by a usually complex cation

-onium

noun suffix

Definition of -onium (Entry 2 of 2)

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

First Known Use of onium

Adjective

1905, in the meaning defined above

History and Etymology for onium

Adjective

-onium

Noun suffix

New Latin, from ammonium

Learn More About onium

Dictionary Entries Near onium

on it

onium

-onium

See More Nearby Entries 

Statistics for onium

Cite this Entry

“Onium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/onium. Accessed 27 Jun. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for onium

onium

adjective
oni·​um | \ ˈō-nē-əm How to pronounce onium (audio) \

Medical Definition of onium

: being or characterized by a usually complex cation onium salts

WORD OF THE DAY

Test Your Vocabulary

Name That Food

  • a-light
  • Name these cookies!
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!