Dictionary
vow'el har"mony
Ling.
a phonological rule in some languages, as Hungarian and Turkish, requiring that the vowels of a word all share a specified feature, such as front or back articulation, thereby conditioning the form that affixes may take, as in forming the Turkish plurals
evler “houses” from
ev “house” and
adamlar “men” from
adam “man.”
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.