-thermysuff. Heat: diathermy.[New Latin -thermia, from Greek therm?, heat, from thermos, warm, hot; see gwher- in Indo-European roots.]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.-thermy n combining form indicating heat: diathermy. [from New Latin -thermia, from Greek therm?] -thermic, -thermal adj combining formCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014-thermy a combining form meaning ?heat,? ?heat generation?: diathermy. [