Designating those Indo-European languages, including the Indo-Iranian, Armenian, and Balto-Slavic subfamilies, in which original palatal velar stops became fricatives (as k' &gt; s or š) and labiovelar stops became plain velars (as kw &gt; k).
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.