Articles: A versus An
Summary: This short handout deals with which article to use before a noun -- "a" or "an."
Contributors:Chris Berry, Allen Brizee
Last Edited: 2010-01-08 12:15:37
How do you know when to use the indefinite articles?
"A" goes before all words that begin with consonants.
- a cat
- a dog
- a purple onion
- a buffalo
- a big apple
With one exception: Use "an" before unsounded h.
- an honorable peace
- an honest error
"An" goes before all words that begin with vowels:
- an apricot
- an egg
- an Indian
- an orbit
- an uprising
With two exceptions: When u makes the same sound as the y in you, or o makes the same sound as w in won, then a is used.
- a union
- a united front
- a unicorn
- a used napkin
- a U.S. ship
- a one-legged man
Note: The choice of article is actually based upon the phonetic (sound) quality of the first letter in a word, not on the orthographic (written) representation of the letter. If the first letter makes a vowel-type sound, you use "an"; if the first letter would make a consonant-type sound, you use "a." So, if you consider the rule from a phonetic perspective, there aren't any exceptions. Since the 'h' hasn't any phonetic representation, no audible sound, in the first exception, the sound that follows the article is a vowel; consequently, 'an' is used. In the second exception, the word-initial 'y' sound (unicorn) is actually a glide [j] phonetically, which has consonantal properties; consequently, it is treated as a consonant, requiring 'a'.
