Articles are words like "a", "an", and "the" that come before nouns and provide information about them. There are three types of articles: "a" and "an" are indefinite articles used for nonspecific nouns, while "the" is the definite article used for specific nouns. Examples are given demonstrating how to identify the article in sentences using "a", "an", and "the" correctly depending on whether the noun is specific or not and whether it begins with a vowel sound.