py·ro·cat·e·chol (p??r?-k?t??-kôl?, -k?l?, -k?l?)n. A biologically important phenol, C6H6O2, having two hydroxyl groups attached to the benzene ring, used in dyeing, tanning, photography, and as an antiseptic. Also called catechol.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.pyrocatechol (?pa?r???kæt??t??l; -k?l) or pyrocatechinn (Elements & Compounds) another name for catecholCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014cat?e?chol (?kæt ??k?l, -?k?l) n. a colorless, crystalline derivative of benzene, C6H6O2, used chiefly in photography, for dyeing, and as a reagent. Also called pyrocatechol. [1875?80; catech (u) + -ol1] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.