hy·dro·cor·ti·sone (h??dr?-kôr?t?-s?n?, -z?n?)n.1. The steroid hormone cortisol.2. A preparation of this hormone obtained from natural sources or produced synthetically and used to treat inflammatory and allergic conditions and adrenal failure.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.hydrocortisone (?ha?dr???k??t??z??n) n (Biochemistry) the principal glucocorticoid secreted by the adrenal cortex; 17-hydroxycorticosterone. The synthesized form is used mainly in treating rheumatic, allergic, and inflammatory disorders. Formula: C21H30O5. Also called: cortisol Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014hy?dro?cor?ti?sone (?ha? dr??k?r t??zo?n, -?so?n) n. a steroid hormone, C21H30O5, of the adrenal cortex, active in carbohydrate and protein metabolism, similar to cortisone in effect. [1950?55] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.