indefinitearticle

The indefinite article is a determiner used before a noun to indicate a non-specific member of a class. In English, the indefinite articles are a and an. They accompany singular count nouns and introduce items as one among many possibilities rather than a particular item: for example, a dog, an idea.

Choice depends on pronunciation: use a before a consonant sound and an before a vowel sound. This is independent of spelling, so a university but an umbrella. Words with a silent h can take an, as in an hour or an heir. Historically, an historic appears in some styles, but not common today.

Indefinite articles are not used with plural nouns or with mass nouns. Instead, quantity is expressed with some or with no article at all: I have dogs; I have some dogs. For professions or roles, the indefinite article is often used: she is a teacher. The article can also convey indefiniteness in single-item contexts, such as I need a minute to think.

Across languages, the indefinite article functions similarly in marking non-specific reference, but the exact form varies. Many languages have dedicated indefinite articles (for example, French un/une, Spanish un/una). Others, such as Russian or Japanese, lack a dedicated indefinite article and rely on context, numerals, or other constructions to express indefiniteness.