monomorphemic

Monomorphemic is a term used in linguistic morphology to describe a word that consists of a single morpheme—the smallest meaningful unit of language. A monomorphemic word cannot be subdivided into smaller morphemic parts that carry meaning. Most monomorphemic words are free morphemes, i.e., units that can stand alone as words, such as book, dog, red, run, or chair. In many languages, such words are the basic building blocks of vocabulary.

In contrast, polymorphemic words are formed from two or more morphemes, such as books (book + -s), happiness (happy + -ness), or reconsideration (re- + consider + -ation). Some words may appear long or morphologically complex but still be monomorphemic if their surface form does not reveal multiple meaningful components, especially when irregular sound changes occur (e.g., went as past tense of go). However, analysis typically regards such forms as single morphemes if no smaller units with independent meaning can be identified.

Determining monomorphemicity involves morphological analysis of the word’s internal structure, often using phonological, etymological, and syntactic evidence. The notion is central to studies of word formation, inflection, and language typology, illustrating how languages build lexicon from one or more morphemes.