Definition and Examples of Monomorphemic Words

In English grammar and morphology, a monomorphemic word is a word that contains just one morpheme (that is, a word element). Contrast with polymorphemic (or multimorphemic) word--that is, a word made up of more than one morpheme.

The word dog, for example, is a monomorphemic word because it can't be broken down into smaller meaningful units, only into sound segments. Another name for monomorphemic is simplex.

Note that monomorphemic words are not necessarily the same as monosyllabic words. For example, the two-syllable words maple and plastic are monomorphemic words.

Examples and Observations

• "An important initial distinction is between monomorphemic words and complex words. As the name implies, monomorphemic words are composed of only a single morpheme or meaningful unit. Examples . . . include friar, sad, and deer: at least in modern English, these words are unanalysable units, and if we understand them it must either be because they are stored as meaningful units in our memory or because a given context in which they appear makes their meaning obvious."
  (Philip Durkin, The Oxford Guide to Etymology. Oxford University Press, 2009)
• "English has borrowed the Russian compound samovar, which consists of the [Russian] morphemes sam 'self' and varit 'to cook.' This compound has entered English without any morphological decomposition: samo and var are meaningless in English, and samovar is thus a simplex word. This shows that morphological rather than etymological criteria should be used when defining complex words . . .."
  (Maria Braun, "Word-Formation and Creolisation: The Case of Early Sranan." Dissertation Universität Siegen. Walter de Gruyter, 2009)
• "An adult speaker of English knows on the order of 10,000 monomorphemic words and 100,000 words total . . .."
  (Janet B. Pierrehumbert, "Probabilistic Phonology: Discrimination and Robustness." Probabilistic Linguistics, ed. by Rens Bod, Jennifer Hay, and Stefanie Jannedy. The MIT Press, 2003)

Morphemes and Syllables

"Be sure not to confuse morphemes with syllables; Mississippi has more than one syllable but is only a single morpheme, at least to speakers who are unaware that its origin, or etymology, is that it comes from the Ojibwa 'big river.' English speakers know that miss and sip in this word are not related to the English uses of those words.

"Words can be monomorphemic, or made up of a single morpheme, such as car and brown, or polymorphemic, made up of more than one morpheme, such as grammaticality, anthropomorphic, linguistics, and racehorse.

"Other examples of monomorphemic words (with more than one syllable) are paper, pizza, Google, river, and catapult (in this last word, cat is a syllable but not a morpheme--it is not related to the feline)."
(Kristin Denham and Anne Lobeck, Linguistics for Everyone: An Introduction, 2nd ed. Wadsworth, Cengage, 2013)

Language Acquisition and Monomorphemic Words

"Brown [A First Language, 1973] emphasized the idea that language development can be predicted by linguistic complexity, with more complex forms acquired after less complex forms. Of particular relevance . . . is his finding that the words produced by children early in their language development are monomorphemic, that is, unmarked by inflections or other bound morphemes, but that subsequently those words become increasingly marked by inflectional suffixes when required by context. Thus, Brown's research is consistent with the proposition that the words used by children in the first years of language development become increasingly morphologically complex."

(Jeremy M. Anglin, Vocabulary Development: A Morphological Analysis. University of Chicago Press, 1993)

Pronunciation: mah-no-mor-FEEM-ik word