A or An?

Brought to you by the Purdue University Online Writing Lab

"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, then a is used.

• a union
• a united front
• a unicorn
• a used napkin
• a U.S. ship

Note: The exceptions for the articles are based upon the orthographic or written representation of the word-initial letter not the phonetic or sound quality of the letter. 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'.

After reviewing this handout, try a practice exercise at http://owl.english.purdue.edu/handouts/esl/esliartEX1.html.

The following information must remain intact on every handout printed for distribution.

This page is located at http://owl.english.purdue.edu/handouts/print/esl/esliart.html

Copyright ©1995-2004 by OWL at Purdue University and Purdue University. All rights reserved.
Use of this site, including printing and distributing our handouts, constitutes acceptance of our terms and conditions of fair use, available at
http://owl.english.purdue.edu/lab/fairuse.html.

To contact OWL, please visit our contact information page at
http://owl.english.purdue.edu/lab/contact.html to find the right person to call or email.