fer·rate \ˈfeˌrāt\noun (-s) Etymology: International Scientific Vocabulary ferr- (from Latin ferrum iron) + -ate : any of various classes of compounds containing iron and oxygen in the anion or regarded as so constituted: as a.: a strongly oxidizing dark red salt analogous to the chromates and sulfates and formed in various ways (as by heating iron filings with a nitrate) < potassium ferrate K2FeO4 > — called also ferrate(VI) b.: ferrite