Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'inion'ModL < Gr, the back of the head < is (gen. inos), sinew, muscle, lit., strength, akin to L vis, strength < IE *wīs- < base *wei-, to strive forward, > L via