What is "tagmeme"

n. (context linguistics tagmemics English) The smallest functional element in the grammatical structure of a sentence.

A tagmeme is the smallest functional element in the grammatical structure of a language. The term was introduced in the 1930s by the linguist Leonard Bloomfield, who defined it as the smallest meaningful unit of grammatical form (analogous to the morpheme, defined as the smallest meaningful unit of lexical form). The term was later adopted, and its meaning broadened, by Kenneth Pike and others, beginning in the 1950s, who used it as the basis for their tagmemics.