Articles are words (or clitics) which serve to introduce and define noun. In English, the articles encode definiteness; they are 'the' (definite) and 'a' (indefinite), and the silent article used with plural indefinite nouns (compare "the cat, a cat, the cats, _ cats").
More complex articlesEdit
In some languages, the article functions as a clitic stem to which other syntactic information can be affixed. This means that the article can also include information about spatial relation, case, or any number of other factors.