“Any of the smallest units of meaning or form within a language, or a verbal element that cannot be further reduced and still retain meaning, e.g. the word ‘woman,’ the prefix ‘un-,’ and the inflection ‘-ize.’ Adjective: morphemic; adverb: morphemically.”
Excerpted from: Grambs, David. The Random House Dictionary for Writers and Readers. New York: Random House, 1990.