Functional morpheme

A functional morpheme (as opposed to a content morpheme) is a morpheme which simply modifies the meaning of the word, rather than supplying the root meaning of the word. That is to say that it functions, but does not mean in and of itself, but rather encodes grammatical meaning.

Functional morphemes are generally closed class, that is, new functional morphemes cannot normally be coined.

Functional morphemes can be bound, such as verbal inflectional morphology (e.g., progressive -ing, past tense -ed), or nominal inflectional morphology (e.g., plural -s), or free, such as conjunctions (e.g., and, or), prepositions (e.g., of, by, for, on), articles (e.g., a, the), and pronouns (e.g., she, him, it, you, mine).