A vs. An – The Indefinitely Mind-Boggling English Rule

Articles? Indefinite? Acronyms?

From time-to-time we all need a little reminder about one grammatical rule or another. Even for many native-English speakers, the usage of the indefinite article “a” or “an” is confusing. We can only imagine what it must be like for non-native English speakers. Let’s settle this mind-boggling English rule!

What Are Articles?

Articles are words that accompany a noun to indicate the type of reference being made by the noun. In the English language, there are three types of articles: definite, indefinite, and partitive.

  • Definite: The word the indicates that its noun is a particular noun or is an identifiable noun to the listener or reader.
  • Indefinite: The words a and an are used before a singular noun that has a plural form.
  • Partitive: Often used to indicate a mass noun, the word some is the English equivalent to a partitive article (e.g., “Would you like some coffee?”).

Can you use articles interchangeably? No. Substituting the for a may change the context and may confuse your readers. Consider the following examples:

  • Give me the glass.
  • Give me a glass.
  • Give me some glass.

A vs. An – Which Is It?

A is used before nouns that begin with consonants, whereas an is used before words that begin with vowels. There are many exceptions, such as using a before a word with the letter u (when pronounced like “you”) and the letter o (when pronounced like “one”). And then there’s that tricky, silent h.

Even though it’s a consonant, that meddling unsounded h is preceded by an (not a) because it’s typically followed by a vowel or vowel sound. When the h is pronounced (or what follows the h is pronounced) like a consonant, use a.

For example:

  • an hour
  • a hill
  • an heir
  • a history

Similarly, in the case of acronyms, a is used before a consonant sound and an is used before a vowel sound. There’s the catch! Watch out for acronyms that are pronounced as one word instead of each letter.

For example, sound out the differences of the following. Notice the distinction between the consonant sound and the vowel sound, especially for those acronyms spelled out and those pronounced as one word.

  • an FBI agent (each letter is pronounced)
  • a FAQ page (pronounced as a word)
  • an FAQ page (each letter is pronounced)
  • an HTML tag (each letter is pronounced)
  • a HIPAA regulation (pronounced as a word)

The be all and end all of this grammatical principle is to rely on the pronunciation of the word in concert with the consonant/vowel rule to determine which is appropriate. When all else fails, ask a friend or even us here at EzineArticles – we’ll give you a hand!

Do you have any questions about weird English rules? Share it below!


davidinnotts writes:

A clear exposition. Thanks, Penny.

But did you know the controversy over whether to pronounce the ‘h’ or not? It depends on local idiom to some extent. In the Caribbean Elgish world, any place there could be an H – aspirated – there will be. My Jamaican friends here in England generally do it the British way, but can forget themselves and begin to add ‘h’s all over the place when flustered! And a Cockney (East London Working Class) speaker will add them when most people wouldn’t. and remove them when others would. So watch out for these dialect differences if you’re trying to imitate.

But historically, did you know that several words which begin with an ‘n’ have had it added quite recently because of the ‘a’/’an’ rule? For example, the word ‘uncle’ used to be spelt (and pronounced) ‘nuncle’, as in “Here cometh mine nuncle”. By Shakespeare’s time, people sometimes dropped the ‘n’ “here comes my uncle” and now it’s always dropped. And all because of the confusion over the rule!

Comment provided January 4, 2013 at 10:17 AM


davidinnotts writes:

Oh dear! Four mistakes in my not-so-immaculate text! Sahme!


Matt Boreau writes:

Wow, I never knew the rules about the acronyms. Thanks for an informative article!

Comment provided January 4, 2013 at 11:11 AM


David James writes:

To make the rule easy to follow, as you point out, it is important to go by the SOUND of the word that follows the a or an.

It’s easy to use “an” before a word that begins with a sound like a vowel but it equally applies when using “a” before a word that begins with the sound of a consonant.

Example: “Let’s look at it from a European perspective.”

Here the beginning of the word European sounds like a consonant, “Y” – Yuropean, hence the “a” is appropriate. “An European” just doesn’t sound right anyway!

Comment provided January 4, 2013 at 1:29 PM


Michael writes:

LOL … I didn’t think I had a problem with this till I read the article.

Now I’m mentally running through every a / an I can think of, to see where / if I’m getting it wrong!

I may even bring it up at my local ‘Get a Life’ club! :-)

Comment provided January 4, 2013 at 1:34 PM


Jeanne Kolenda writes:

I heard something this morning that gave me pause…is it correct (or considered a double-negative no-no) to say…”that is not uncommon?” Or should it be…”that is common.” Both seem ok to me…what do you think?

Comment provided January 4, 2013 at 2:07 PM


davidinnotts writes:

Hi, Jeanne. Confusingly, while a double negative should be cancelled out, and usually is, there are idiomatic expressions whose meaning has shifted from the obvious in all languages, and this is particularly true in English. So the double negative “that is not uncommon” ought to mean the same as “that is common”. But it doesn’t because of the shift in meaning.

The English are noted for understatement, especially to invoke dry humour. “That is common” means what it obviously says. But “That is not uncommon” suggests that it is VERY common, with a sense of irony that the person spoken to ought to have found the question too obvious to ask. It’s a subtle difference, but the use of such a double negative adds huge depth to what is otherwise just a statement of fact.


Edmund writes:

As much as I hate to point it out, “That is common” also can be taken to mean proletarian or lower class so needs to be used in context. “That is not uncommon” does not suggest VERY common or frequent it only suggests the opposite of rare or never. Therefore, “it is not uncommon for a politician to receive a bribe” does not suggest that all politicians are bribed but suggests that it does happen.


RankMySiteSEO writes:

I can’t believe how many people just aren’t clear on this so thanks for the article!

Comment provided January 4, 2013 at 2:33 PM


Michael writes:

I realised I ‘knew’ the rules, even though I didn’t ‘know’ there were rules. (OK, I did, but I didn’t know I knew them!)

One of the most useful books I’ve ever read on the broader theme was ‘English grammar for students of German’. Taught me all sorts of grammatical things in English first, so I could understand the German equivalent.

I think my English Grammar ‘O’ level certificate must be a forgery. I learned more from reading that book than I ever did in the classroom!

Comment provided January 4, 2013 at 4:05 PM


Nelida K. writes:


Clear and to the point, well done.

However, I have one objection (and I am not a native English speaker):

You write, regarding acronyms:

“in the case of an acronyms”.

I believe that the “an” should be deleted, and that you intended to write “in the case of acronyms”. IMHO.

Greetings, and best wishes for a prosperous 2013.

Comment provided January 4, 2013 at 5:28 PM



Good catch! That was indeed a typo and it has since been fixed. Thanks for your attention to detail. :-)



Sybille Conrad writes:

In spoken American English the “h” in herbs appears to be dropped, and I have seen “an herb” which, to me, looks totally incorrect. Can you please clarify?

Best Wishes for 2013

Comment provided January 4, 2013 at 6:25 PM


davidinnotts writes:

Yep! As I said above, Sybille, there are variants across the English-speaking world, some of them quite extreme. But most people know the UK/US/Oz norms and find them acceptable.

So the ‘h’ in herb is usually dropped, and needs an ‘an’ in front, but this is not the practice everywhere. And while most people aspirate each ‘h’ in “high, hot, hirsute, hapless heffalump”, in Cockney and several other English dialectsyou’d leave them all off, pronouncing it: ” ‘igh, ‘ot, irsuit, ‘apless ‘effalump”. But even these will know the standard form and expect to read it. So, as Penny says, listen to how it sounds and go that way. Ten even the variant spellings, as David James pointed out above, get picked up.


Edmund writes:

Yes, “an herb” is wrong but “an herbaceous border” would be right.


davidinnotts writes:

Right, Edmund, if you’re among the majority who now pronounce ‘herb’ sounding the ‘h’. But some still call it an ‘erb; among them are plenty in the British ‘upper crust’ and a huge number of people who drop the ‘h’ in casual or rapid speech, but ‘know’ that it’s actually correct to pronounce it. And outside the UK, it’s even more confusing!


Joaseph Dabon writes:

Does look confusing especially for people who are not fond of reading and writing.

Comment provided January 4, 2013 at 8:15 PM


Lisa writes:


You really know your stuff.

Comment provided January 4, 2013 at 9:40 PM


Terence Starkey writes:

Interesting article, but after some thought I realised that if you have been schooled in the English language from childbirth, it is no longer a problem – you automatically use the correct article.

Comment provided January 4, 2013 at 10:52 PM


Randall Magwood writes:

I learned this lesson really well in middle school lol.
But “an FBI agent”, or “an one hundred dollars” always confuses me. From logic, it would seem that “a FBI agent” or “a one hundred dollar bill” would fall in line with convention. But I guess not. Great post.

Comment provided January 5, 2013 at 12:56 AM


davidinnotts writes:

Ah, Randall: there’s another element that kicks in here – that 100 is both a number and a plural, so ‘a’ or ‘an’ don’t apply.

But if you want to say ‘a hundred dollars’ rather than ‘one hundred dollars’, that would be fine – a unit of 100 dollars is a single item; it’s singular (think of it as a bundle of bills in a wrapper). You can’t use both ‘a’ and ‘one’ together.

And thinking about just a single dollar, the same applies: you can say, “Here’s a dollar” or “Here’s one dollar” but not “Here’s a one dollar”.


davidinnotts writes:

Aaaand I’ve just realized: what about the expression, “A one hundred dollar bill”, which is correct English. Why not ‘an’? The answer is that you’re actually saying “A hundred dollar bill”, and “An hundred dollar bill” would be plain wrong. The ‘one’ is an adjective, like the ‘hundred’, emphasizing that there’s only one bill, and the indefinite article ‘a’ applies to the object, the bill.

Comment provided January 5, 2013 at 6:14 AM


Michael writes:

I’ll have to remember that next time someone asks if they can still get a one pound note as well as a one pound coin! :-)


Michael writes:

LOL … sorry David … was trying to reply to your previous post before I read this one! :-))


Michael writes:

Also – and perhaps more simply – we’re back to the ‘sound’ thing again.

“A one hundred dollar bill” is pronouned “a won hundred dollar bill”, “an FBI agent” is pronounced “an ef-bee-eye agent” [ sorry, don’t know proper phonetics!] …

Perhaps that’s why on TV they say “I am a federal agent” so often. Avoids the confusion. ;-)


David Burdon writes:

An acronym is an abbreviation that is sounded as a word. E.g. NATO.
The term abbreviation includes both acronyms and other abbreviations that are sounded sounded as words such as the BBC. There’s a tendency to make more abbreviations acronyms. Especially where stop words such as The and A are used.

Comment provided January 5, 2013 at 6:59 AM


Paul Bessell writes:

Why has no-one mentioned ‘an hotel’?

Comment provided January 6, 2013 at 8:30 AM


Michael writes:

Because it’s very rarely used nowadays …. most people say “an ‘otel” or “a hotel” … back to the ‘sound’ rule again.

To be honest – and certainly not meaning to be rude about anyone who does – I think “an hotel” is really only used by those people who are trying to demonstrate how well they (think they) know the language!


Edmund writes:

I agree completely, I believe that this is correct, “an hotel” as in “an historical character”, in both words the H is actually pronounced but is, I suppose, a soft H rather than a hard one.


Randall Magwood writes:

Thanks David with the clear insights. I appreciate it.

Comment provided January 6, 2013 at 6:45 PM


Jose Quintero writes:

I have been in places that writes A at all times when preceding a word with H because is considered as a consonant. Personally I follow your rules.

Comment provided January 6, 2013 at 10:31 PM


Luiz writes:

Hey, hi everyone.

My question is simple, it is a bout a word:

The correct is ‘a sleepwalker’ or ‘an sleepwalker’?

Sorry if it is a simple ask, its because i saw some articles and people using ‘an’ and some using ‘a’, i am not native and i didnt found nobody to explain to me.

Thanks a lot, and nice article, again.


Comment provided January 7, 2013 at 8:38 PM



It would be ‘a sleepwalker’.



Luiz writes:

Thank you Marc,

some people claim that have a vowel sound.

Let me ask, have any word starts with consonant and receive ‘a’, except the words begin with ‘h’?

I am studying English and I really wanna learn that.

Thank you so much.



Michael writes:

I’m really struggling to think of any examples that don’t fit with the “starts with a vowel – takes ‘an’; starts with a consonant – takes ‘a'” rule.

Someone earlier mentioned “an hotel” … is / was correct English, but it’s VERY old-fashioned … very few people actually use it, either in spoken or written English, and language is after all about communicating and being understood!


davidinnotts writes:

Yes, Luiz.

I don’t know how it works in your language, but in English, it’s hard to pronounce two vowels separately, one after the other, and the same with two consonants separately, one after the other – it sounds like a hiccup between them. This is what the ‘a’/’an’ rule is based on. Of course, I don’t mean letter combinations to make another sound, like ‘beak’ not be-ak’, where English is the most diverse (and inconsistent) language in this that I’ve come across.

Because ‘sleepwalker’ begins with a consonant, it needs a vowel, ‘a’ before it, not ‘an’. But nouns that begin with a vowel (that is, the spoken sound begins with a vowel) have ‘a’ before them. It’s surprising how many people – even native speakers – get this wrong in writing, when they’d never slip that way when they speak. So you will see ‘a’ and ‘an’ used incorrectly when writing, even by people who would always say it correctly.

Of course, if you don’t know exactly how the word is meant to sound, that makes it hard to choose! And native English speakers across the world do disagree on this. As writers needing to appeal to the most people, we’d best go for the most common usage.


Edmund writes:

This is similar in Spanish where Y (and, pronounced eee) is changed to E (pronounced a)when the subsequent word begins with an I (pronounced eee) and O (or) is changed to U when the subsequent word starts with an “o”. In both cases this is the rule if there is a silent “h” before the vowel.


Gracious Store writes:

Thank you for these reminders in using articles. They can indeed be very confusing!

Comment provided January 30, 2013 at 11:11 PM


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