ni·trate (n??tr?t?, -tr?t)n.1. The univalent anionic group NO3, derived from nitric acid, or a compound containing this group.2. Fertilizer consisting of sodium nitrate, potassium nitrate, or ammonium nitrate.tr.v. ni·trat·ed, ni·trat·ing, ni·trates To treat with nitric acid or a nitrate, usually to change (an organic compound) into a nitrate.ni·tra?tion n.ni?tra?tor n.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.nitrate (?na?tre?t) n1. (Elements & Compounds) any salt or ester of nitric acid, such as sodium nitrate, NaNO32. (Agriculture) a fertilizer consisting of or containing nitrate saltsvb3. (Chemistry) (tr) to treat with nitric acid or a nitrate4. (Chemistry) to convert or be converted into a nitrate5. (Chemistry) to undergo or cause to undergo the chemical process in which a nitro group is introduced into a molecule ni?tration nCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ni?trate (n. ?na? tre?t, -tr?t; v. -tre?t) n., v. -trat?ed, -trat?ing. n. 1. a salt or ester of nitric acid, or any compound containing the univalent group ONO2 or NO3. 2. fertilizer consisting of potassium nitrate or sodium nitrate. v.t. 3. to treat with nitric acid or a nitrate. 4. to convert into a nitrate. [