ker·a·to·sis (k?r??-t??s?s)n. pl. ker·a·to·ses (-s?z) Excessive growth of horny tissue of the skin.ker?a·tot?ic (-t?t??k) adj.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.keratosis (?k?r??t??s?s) n1. (Pathology) any skin condition marked by a horny growth, such as a wart2. (Pathology) a horny growthCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ker?a?to?sis (?k?r ??to? s?s) n., pl. -ses (-s?z). 1. any skin disease characterized by a horny growth, as a wart. 2. any horny growth. [1880?85] ker`a?to?sic, ker`a?tot?ic (-?t?t ?k) adj. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.