Originally proposed by Ferdinand de Saussure, "linguistic unit" is a phrase used by linguists to describe any piece of linguistic data (that is, something uttered by a speaker) that it makes sense to talk about as a single bit. The beauty of the phrase is that it is non-specific and so can be used in any subdiscipline from phonetics to semantics to sociolinguistics. Furthermore, it can help avoid using such vague language as "word", for which there is no agreed-upon definition. The phrase is also very useful in defining concepts like morpheme: the smallest linguistic unit that expresses meaning; it seems that without a non-specific term like "linguistic unit" morpheme could not be defined.

For example, the following can be considered linguistic units: