Used before nouns and noun phrases that denote a single but unspecified person or thing: a region; a person.
Used before terms, such as few or many, that denote number, amount, quantity, or degree: only a few of the voters; a bit more rest; a little excited In writing, the form a is used before a word beginning with a consonant sound, regardless of its spelling (a frog, a university). The form an is used before a word beginning with a vowel sound (an orange, an hour). ·An was once a common variant before words beginning with h in which the first syllable was unstressed; thus 18th-century authors wrote either a historical or an historical but a history, not an history. This usage made sense in that people often did not pronounce the initial h in words such as historical and heroic, but by the late 19th century educated speakers usually pronounced initial h, and the practice of writing an before such words began to die out. Nowadays it survives primarily before the word historical. One may also come across it in the phrases an hysterectomy or an hereditary trait. These usages are acceptable in formal writing.

Favorite interjection of The Fonz.

The smallest bra size available besides a double A; first REAL bra size even though it is very small.

The first letter in the English alphabet.

Where one gets f'd.

First used on South Park

1) the first letter of the English alphabet
2) a sound that this letter represents
3) one; one sort of
4) each; any one
5) in or for each
6) in some schools, the highest grade, meaning "excellent" or "best"
7) in music, the sixth tone or note in the scale of C Major
8) abbreviation for assist: used in sports

The first letter in the english alphabet. Used before a noun to indicate a single type or example.

An alternative to saying, "Yes, you are right"