Designating those Indo-European languages, including the Indo-Iranian, Armenian, and Balto-Slavic branches, in which original palatal velar stops became fricatives (as k' > s or š) and labiovelar stops became plain velars (as kw > k).
[Avestan satəm, hundred (a word whose initial sound illustrates the change); see dek in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.