-stomysuff. A surgical operation in which an artificial opening is made into a specified organ or part: colostomy.[Greek stoma, opening, mouth + -y.]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.-stomy n combining form (Surgery) indicating a surgical operation performed to make an artificial opening into or for a specified part: cytostomy. [from Greek -stomia, from stoma mouth]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014-stomy a combining form used in the names of surgical operations that involve the establishment of an artificial opening into or between the part or parts specified by the initial element: colostomy. [