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"A" vs. "An" - When to Use

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  Ed Good  —  Grammar Tips
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A Historic Topic - A vs. An

Writers sometimes confuse the use of the articles a and an. We were all taught that a precedes a word starting with a consonant and that an precedes a word starting with a vowel (a, e, i, o, u, and sometimes y).

Here’s the secret to making the rule work: The rule applies to the sound of the letter beginning the word, not just the letter itself. The way we say the word will determine whether or not we use a or an. If the word begins with a vowel sound, you must use an. If it begins with a consonant sound, you must use a.



For example, the word hour begins with the consonant h. But the h is silent, so the word has a vowel sound. Hence:

an hour

The rule works the other way as well. Take the word university. It begins with the vowel u. But the u is pronounced as if it begins with the consonant y. Hence:

a university

But consider the word umbrella, also starting with u. It starts with the vowel sound uh. Hence:

an umbrella

Another vowel with a consonant sound is o. When spoken, the letter can sound as if it begins with the consonant w. Thus, we use the a:

a one-room apartment a once-famous actor

Articles with Words Beginning with ‘h,’ a or an

The consonant giving us the most trouble is probably h. When the h begins a word and the first syllable is strongly pronounced, you should use a.

a history of Europe (accent falls on his) a hero (accent falls on he)

But when the beginning h is weakly pronounced (historic, habitual), you may use an, especially in British English.

an historic occasion (hisTORic) an habitual offender (haBITual)

But these usages are becoming increasingly old-fashioned, so you may also use a.

a historic occasion a habitual offender

Articles with Acronyms, a or an

Finally, the rule applies to acronyms as well. If you pronounce a letter as a letter and it begins with a vowel sound, you should precede it with an. The consonants with vowel sounds include f, h, l, m, n, r, s, and x.

He flew in an SST. He fired an M‑1. He attended an FDA hearing.

By the same token, if a vowel letter, with a consonant sound, is pronounced as a letter, you should use a.

He made a U‑turn.

Got it? So what is your grade?

An A? A B? Surely not an F.

Hard Copy

You may download our entire discussion of the Parts of Speech. Simply download the Grammar eBook Understanding the Parts of Speech.

 

Previous: A, An, The - The Articles Next: Other One-Word Adjectives

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25 Comments

  • While using the term NCS (Networked Control System), should we use the term as 'a NCS' or 'an NCS'
    LikeReplyReport3 months ago
    • If you say in your mind when you read the letters NCS ("en see es:"), then the letter N is pronounced beginning with a short "e" sound. So you would use "an NCS". If you say in your mind, Network Control System when you see the acronym, then you would use "a NCS" as YOU read this as "a Network Control System" even though there are only 3 letters written in the document. 
      LikeReplyReport2 months ago
  • 990 stars
    LikeReplyReport 19 months ago
  • what about symbols like ~ for approximately before a word or number. Do you use the sound of the symbol or the word after ( an ~3 acre area or a ~3 acre area)
    LikeReplyReport 11 year ago
    • If you say "approximately" when you read it (or say it in your mind), then you use "an". If you skip over the "~" when you read it, then you use "a".
      LikeReplyReport2 months ago
  • What about the following?
    An Historic Neighborhood Community
    A or An
    LikeReplyReport1 year ago
    • The author talks about this. Look in the article for "historic".
      LikeReplyReport2 months ago
  • I am still thinking what are we supposed to look for then? Are we only supposed to look for ah and uh vowel sound?
    Like h silent, ah=an for hour and uh/uhm= an for umbrella?
    If a vowel or word gets yu vowel sound then that becomes a ?
    Trying to understand this interesting concept :) 
    LikeReplyReport1 year ago
    • it is very simple...if a word begins with the sound of a vowel then you use "an" before it. If a word begins with the sound of a consonant then you use "a" before it
      LikeReplyReport 41 year ago
  • Thanks!!!
    LikeReplyReport 12 years ago
  • This is gold, Jerry. Gold!
    LikeReplyReport 42 years ago
  • Most of the parts were quite helpful. Thank you.
    I am not sure about U-turn though.
    LikeReplyReport 22 years ago
  • I've been speaking english all my life and this info just never occured to me. I'm quite mind blown!
    LikeReplyReport 22 years ago
  • SST is not an acronym. M-1 isn't, nor is FDA.

    Should we trust your opinion when your article includes such errors?
    LikeReplyReport2 years ago
    • SST stands for supersonic transport. I would call that an acronym. The Free Dictionary places M-1 under an acronym listing. FDA is an anacronym that stands for Food and Drug Administration. What is your definition of an anacronym? 
      LikeReplyReport 42 years ago
    • Claudia Carlsen An acronym is a type of abbreviation in which the first letters of the words being abbreviated form a pronouncable word such as NASA, LASER, and RAM. In contrast, an initialism is not pronounced as a word, for example, FDA, M-1, SST.
      Dictionaries are starting to define acronym to include initialisms because they are so commonly confused. 
      LikeReplyReport 42 years ago
    • Tams Fletcher Thank you Tams, I learned something new today. Both from you and the article. However splitting hairs apart, this article was already a lot for me, someone who speaks very good english. I can imagine they wanted to keep it a bit simpler because otherwise people who really want this information (English language students) would not be able to find this article useful, but just too overwhelming. 
      LikeReplyReport 22 years ago
  • thanks for the useful info
    LikeReplyReport 22 years ago
  • Thanks for these tips! I just read a publicly posted US government document where they used "a" before the abbreviation "FFS" and it seemed wrong to me. Your article confirmed that my teachers in India taught me correctly. 
    LikeReplyReport 12 years ago
  • Why teachers! WHY! (to my HS teachers)
    LikeReplyReport 12 years ago
  • thank you
    LikeReplyReport 12 years ago
  • Cleared up a debate at work...I was wrong.
    LikeReplyReport 23 years ago
  • Great information. Very easy to understand and use. You know more than all the experts!
    LikeReplyReport 43 years ago
  • Well done.
    LikeReplyReport 14 years ago
  • Very usefull post. Thanks to Kathleen for the addition.
    LikeReplyReport 25 years ago
  • Recently in th newspaper there was reference to "an New Jersey...: I have seen this before elsewhere-Why?
    LikeReplyReport 15 years ago
  • Ahead of the letter R when it's the first letter in an abbreviation. As in "An R.O.E." or "A ROE"
    LikeReplyReport 15 years ago
  • Great post but not awsome, things like the Aurora Borealis are awsome!
    LikeReplyReport 35 years ago
  • Awesome post!
    LikeReplyReport 25 years ago
  • an independant organization-OR-a independent organization?
    LikeReplyReport 15 years ago
    • An. The 'n' makes the pronunciation easier, which is the origin of "an" vs. "a".
      LikeReplyReport 25 years ago
    • Karen Everett Lewis There is a vitamin advertisement on TV and the girl says "the vitamins are approved by a independent organization". It sounds wrong!
      LikeReplyReport 25 years ago
    • Chip Jones That's definitely wrong. I am finding several wrong usages online these days. There are people who are using "a" incorrectly. It's becoming the norm and it's annoying.
      LikeReplyReport2 years ago
  • o ho god why are you create the english language.?
    LikeReplyReport 36 years ago
  • Find it a little confusing ,with the "an" rule must follow consonants is not consistent .Surely there must be an easier explanation!!!
    LikeReplyReport 66 years ago
    • There is Stanley. If you are talking about AN ITEM then use AN. If you are talking about two or more things, then use AND. (She and I) (An apple)
      LikeReplyReport 16 years ago
    • Teressa Allen what about for a & an (an elephant) OR (an hour) or (a hour)
      LikeReplyReport 16 years ago
    • Kanocia Gayden i'ts all about the sound.,, :D
      LikeReplyReport 25 years ago

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