Webster's Revised Unabridged Dictionary · 1913

anionic

anionic , adjective

1.
having the character of an anion; negatively charged; containing anions; -- of atoms, molecules, and groups of atoms. Contrasted with cationic.
2.
of or pertaining to anions. Contrasted with cationic

anionic , noun

1.
a class of synthetic detergents in which the molecules do not ionize in aqueous solutions.