phosphonium[fäs fō′nē əm]
phosphonium definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
the monovalent radical PH, which is related to PH as the ammonium radical NH is related to NH
Origin: ModL: see phosph(o)- and amp; -onium
phosphonium definition by American Heritage Dictionary
A univalent radical, PH4, derived from phosphine.
Origin: phosph(o)- + (amm)onium.