war·fa·rin (wôr?f?r-?n)n. A white crystalline compound, C19H16O4, that inhibits production of prothrombin and is used in the form of its sodium salt as an anticoagulant drug and as a rodenticide.[W(isconsin) A(lumni) R(esearch) F(oundation) + (coum)arin.]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.warfarin (?w??f?r?n) n (Elements & Compounds) a crystalline insoluble optically active compound, used as a rodenticide and, in the form of its sodium salt, as a medical anticoagulant. Formula: C19H16O4[C20: from the patent owners W(isconsin) A(lumni) R(esearch) F(oundation) + (coum)arin]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014war?fa?rin (?w?r f? r?n) n. 1. a crystalline anticoagulant, C19H16O4, used as a rodenticide. 2. a preparation of this used in the management of clotting disorders. [1945?50; W(isconsin)A(lumni)R(esearch)F(oundation) (owners of patent) + (coum) arin] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.