Definition & Meaning of "function word"

What is a "function word"?

A function word is a type of word that has little lexical meaning but serves to express grammatical relationships between other words within a sentence. These words help convey the structure and meaning of sentences by indicating things like tense, mood, conjunctions, and prepositions. Examples of function words include articles like "the" and "a," prepositions like "in" and "on," conjunctions like "and" and "but," and auxiliary verbs like "is" and "have." Understanding function words is important for grasping how sentences are constructed and how meaning is communicated in language.