-omasuff. Tumor: lipoma.[New Latin -?ma, from Greek -?ma, -?mat-, n. suff.]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.-oma n combining form indicating a tumour: carcinoma. [from Greek -?ma]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014-oma pl. -omas, -omata. a noun suffix used to form names of tumors, of the kind specified by the base: fibroma; melanoma. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.