Pan-Hel·len·ic also Pan·hel·len·ic (p?n?h?-l?n??k)adj.1. Of or relating to all Greek peoples or a movement to unify them.2. Of or relating to all Greek-letter fraternities and sororities.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.