Perhaps Wikipedia describes this best when explaining that an article is a word that combines with a noun to indicate the type of reference being made by the noun. Articles specify the grammatical definiteness of the noun. The articles in the English language are the, a, and an.

Definiteness refers to how identifiable the noun is to the reader or the listener. For example, there is a noticeable difference between the following two examples:

“Raise the flag.”

“Raise a flag.”

Subchapters