trigraph definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a group of three letters representing one sound (Ex.: pph in Sappho)
Origin: tri- plush -graph
trigraph definition by American Heritage Dictionary
- Three letters spelling one consonant, vowel, or diphthong, such as Sch in Schiller or igh in high or thigh.
- A group of three letters, especially of frequent occurrence in a given language, as the or ing in English or gli in Italian.
- Any combination of three letters of an alphabet. Also called trigram.