Pronunciation: (môr'fēm), [key]
any of the minimal grammatical units of a language, each constituting a word or meaningful part of a word, that cannot be divided into smaller independent grammatical parts, as the, write, or the -ed of waited. Cf. allomorph (def. 2), morph (def. 1).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.