-onium


Chemistry.

a suffix used in the names of complex cations: oxonium.

Origin of -onium

extracted from ammonium
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Medicine definitions for -onium

-onium

suff.

Containing a positively charged radical:carbonium.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.