Dictionary
an•i•on
Pronunciation: (an'ī"un), [key]—
n. Physical Chem.
1. a negatively charged ion, as one attracted to the anode in electrolysis.
2. any negatively charged atom or group of atoms (opposed to
cation).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.