A vs. An: Should I Use A or An?
The Blue Book of Grammar and Punctuation
A vs. An: Should I Use A or An?
You probably use a and an in writing and speech every day. Do you also know which one is proper in each usage? In today’s post we’ll clear up any confusion you might have about a and an.
Both a and an are indefinite articles, which are words that refer to a person or a thing that is not identified or specified.
I bought a book yesterday.
Cindy had a banana before lunch.
Robbie saw an elephant at the zoo.
You can see that both a and an play the same role. So what is the difference between them?
Knowing When to Use A or An
A long-standing rule that you might have learned along the way is to use a before a word that begins with a consonant and an before a word that begins with a vowel (a, e, i, o, u).
That guideline gives you almost enough information, as we can see in the following pair of sentences.
I slept through a long flight.
I slept through an entire flight.
You see the adjustment in how we adjust a to an when the following word begins with a vowel (entire).
However, that’s not the whole story. The main indicator in knowing when to use a or an is how the following word sounds. As we’ve pointed out, using a or an will depend on the first letter of the next word. We will use a when the first letter of the next word has a consonant sound (including y and w). We will use an when the first letter of the next word has a vowel sound.
Also keep in mind that some letters, notably h and u, act sometimes as consonants (home, usual) and sometimes as vowels (honest, unusual).
Examples: Indefinite Article Followed by Consonant Sound
a yearning
a hotel
a U-turn (pronounced “yoo”)
a NASA study
Examples: Indefinite Article Followed by Vowel Sound
an unfair charge
an honor (the h is silent)
an HMO plan (H is pronounced “aitch”)
an NAACP convention (the N is pronounced “en”)
Now let’s look at this principle applied to two sentences stating similar thoughts.
He was a half hour late for class.
He was an hour late for class.
In the first sentence, the word after the indefinite article (half) begins with an h, and it is spoken with a detectable consonant sound. We therefore use the indefinite article a before the consonant sound.
In the second sentence, the word following the indefinite article (hour) likewise begins with an h, but this time it is pronounced as a softer vowel sound, as in the word our. We therefore precede the vowel sound with the indefinite article that ends in the consonant n, an.
Related Topic
A or An vs. The
Pop Quiz
Complete each sentence with the correct use of a or an.
1. I got _____ raise from my boss this month.
2. Could you spare _____ extra 15 minutes to sign my petition?
3. Kristen got _____ MBA degree.
4. John doesn’t know _____ thing about plumbing.
5. It’s nice to start _____ new day with fresh coffee.
Pop Quiz Answers
1. I got a raise from my boss this month.
2. Could you spare an extra 15 minutes to sign my petition?
3. Kristen got an MBA degree.
4. John doesn’t know a thing about plumbing.
5. It’s nice to start a new day with fresh coffee.
Are you ready for the quiz?
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A and An are both English indefinite article. As mentioned, we use A before a noun commencing by a consonant sound and An before a vowel sound. It is not correct though to state those two rules in the following ways: A is used before a noun commencing by a consonant eg: a ewe. Here we have used the indefinite article A before a noun starting by -e but sounding consonant [ju:]. Also, it isn’t correct to say that An is used before a noun starting by a vowel. Eg: An MP (Member of Parliament) an is used here before a consonant but sounding vowel [em pi].
The second half of the article discusses indefinite articles followed by consonant and vowel sounds (as opposed to letters).
Why Use an MBA degree as question number (3)? What is the logic of that?
Kristen got an MBA degree.
Initialisms are pronounced with a starting vowel sound (“em”-bee-ay) or starting consonant sound (“eff”-bee-eye). This will influence whether to precede the initialism with “a” when the first following sound is a consonant or “an” when the following sound is a vowel.
A vs an
Provided that a Agreement for Payment is received….
or
Provided that an Agreement for Payment is received…
As the post indicates, use an before a word that begins with a vowel sound. Therefore, write “…an Agreement…”
What about the word use, that sounds like it starts with a Y? Is that proceeded by “a” or “an”? I’m writing the sentence “… or a ‘use other door’ sign…” and wonder if I should add the n. Honestly, since I’m not sure, I’ll change the sentence to “…or a sign reading ‘use other door’…” but if I would like to know for future use which is correct.
As the post states, “In knowing when to use a or an, we should also consider how the following word sounds.” In other words, the sound supersedes the letter in using a or an. We would use a before words beginning with a consonant as well as y and w sounds. The word “use” starts with a y sound, so it would be preceded by a.
Please suggest the correct use of article in the sentence “The analysis was conducted on a Waters Alliance 2695 separation model.”
Your sentence is correct as written.
What if the indefinite article is followed by parentheses or a phrase separated by dashes? Do you determine the indefinite article by the first word in the parentheses or the first word after? Example:
“This is the result of a/an — in my honest and sincere opinion — mythical description of human nature.”
The indefinite article a refers to “mythical description” in your example sentence.
“This is the result of a—in my honest and sincere opinion—mythical description of human nature.”
You could also rewrite as follows:
“This is the result of a mythical description of human nature (in my honest and sincere opinion).”
“In my honest and sincere opinion, this is the result of a mythical description of human nature.”
“This is, in my honest and sincere opinion, the result of a mythical description of human nature.”