The indefinite articles “a” and “an” modify different types of singular count nouns. The “a” article proceeds words that begin with a consonant sound, while “an” proceeds words that begin with a vowel sound.
What is the difference between a vs. an?
One of the most common grammar errors is mixing up indefinite articles a and an. Each article proceeds singular, noncount nouns to convey relationships between words in a clause. But the way we use a and an also depends on English phonetics, which is a complex topic in itself.
Overall, we use the article a before words that begin with a consonant (e.g., C, B, T), and we use the article an before words that start with a vowel (i.e., I, E, A, O, U). There is one big exception to this rule, though. Whether it’s for regular nouns, acronyms, initialism, or abbreviations, if the first letter sounds like a vowel, we use the article “an” instead of “a.”
If you’re new to English or a native speaker, The Word Counter’s simple grammar guide can help you review basic grammar rules, terminology, and understand how articulation affects the use of articles like a and an.
What are articles and what do they do?
A and an are examples of articles. An article is a type of determiner, which is a class of words that interact with nouns. There are several types of English determiners, which include:
- Articles: the, a, an.
- Possessive nouns: teacher’s, mom’s, Jack’s, etc.
- Possessive pronouns: hers, your, whose, their, etc.
- Numbers: zero, one, five, ten, etc.
- Indefinite pronouns: all, any, both, each, either, every, etc.
- Demonstrative pronouns: that, these, this, those, such, etc.
All determiners are modifiers because they alter nouns, but not all modifiers are determiners. For example, adjectives modify pronouns and nouns, while adverbs modify adjectives, verbs, and other adverbs. Articles only modify nouns.
Indefinite vs. definite articles: A, an, and the
There are three types of articles in the English Language: the, a, and an. “The” is a definite article because it refers to a specific or definite noun in a clause. For example,
“I’m walking to the store.”
“What’s the password?”
A or an are indefinite articles because they refer to a nonspecific or indefinite noun in a clause. For example,
“I’m eating an apple.”
“I need a unicorn.”
Articles modify four types of nouns
Now that we understand which articles modify definite and indefinite nouns, let’s talk about the different types of nouns we can work with:
- Singular noun: A single person, place, or thing (ex: ball, tree, or friend).
- Plural noun: A group of people, places, or things (ex: balls, trees, or friends).
- Count noun: A noun that’s capable of singular and plural forms (ex: tree and trees).
- Noncount noun: A noun that is singular or plural (ex: flour, pavement, or gratitude).
Each noun category pairs together to make four definite or indefinite noun types:
- A singular or plural count noun (e.g., person/persons or cat/cats) or,
- A singular or plural noncount noun (e.g., coffee or water).
Which nouns use the or a/an articles?
Singular count nouns can represent a specific or nonspecific object, so they can use the or a/an. A specific object (definite) uses the, while a nonspecific object (indefinite) uses a or an. For example,
Definite noun: “We’re at the school called Jefferson Elementary.”
Indefinite noun: “We’re at a school.”
Indefinite noun: “We’re at an academy.”
For definite plural count nouns, singular noncount nouns, or plural noncount nouns, we only use the article the. When these nouns are indefinite, we use different determiners or no determiner at all.
A vs. an: consonants vs. vowels
In summary of the section above, we only use a and an with indefinite, singular count nouns. But there are other basic rules involving phonetics, which is the study of speech sounds that we hear in languages.
English speakers use a variety of sounds to speak, but two of the main “phones” are consonants and vowels. Consonants are the sounds made while pronouncing letters that require airflow restriction through lips, teeth, or the tongue. We can break down different types of consonants made with specific articulatory organs, such as,
- Bilabial: p, b, m.
- Labiodental: v, f.
- Dental: th, dh (the “th” of ‘thought’).
- Alveolar: s, z, t, d.
- Palato-alveolar: sh, ch, zh (the “si” of ‘asian’), jh (the “j” of ‘jade’).
- Palatal: y.
- Velar: k, g, ng (the “ng” of ‘king’).
- Glottal: q.
You may also notice how consonants do not include letters like A, E, I, O, or U. That’s because these letters are vowels, which have different pronunciations.
Vowels are the sounds we make to pronounce the letters A, E, I, O, and U, but each letter possesses a variety of sounds that depend on tongue position, and whether the letter follows or precedes another vowel or consonant.
For example, the letter A requires different tongue positions in the mouth for certain pronunciations:
- Lower front: “ae” (answer).
- Lower middle: “ah” (aunt), “aw” (awesome).
- Lower back: “aa” (parse), “ao” (autumn).
- Middle-back: “ax” (ambrosia), “ow” (oat).
- Font-middle: “ey” (daze), “ey” (bait).
- Front-top: “iy” (eat).
As shown above, we pronounce vowels very differently when it accompanies other consonants and vowels in a word. But this is also why articles like a and an attend different terms.
Why do we use a and an differently?
We use the articles a and an differently because their separate pronunciations allow us to enunciate the following word correctly. For instance, try pronouncing the following incorrect phrases:
- “An centerfold.”
- “A eater.”
- “An mission.”
When we pronounce these phrases aloud, it’s difficult to know whether we said one word or two. The consonant within the second letter of “an” is important to use before the next word (a vowel) because it indicates how they are separate terms.
How to pronounce and use a/an articles
We pronounce a as ‘ah’ with our tongue positioned in the lower-middle part of the mouth, and we place the article a in front of singular count nouns that begin with a consonant sound. For example,
“A boat” (ah b-ow-t).
“A phone” (ah f-ow-n).
“A mother” (ah m-ah-dh-er).
In contrast, we pronounce an as ‘ae-n’ with our tongue in the lower-front of the mouth, and we use the article before words that begin with a vowel sound. For example,
“An eagle” (ae-n iy-g-ah-l).
“An orb” (ae-n ao-r-b).
“An ulcer” (ae-n ah-l-s-er).
Words with vowels sounds vs. vowels with consonant sounds
Words that begin with a vowel-like sound don’t always begin with a vowel. For instance, we pronounce the beginning of certain words like “honor” or “FBI” with vowel sounds. Therefore, we use the article an instead of a. For example,
“An honor” (ae-n aa-n-er).
“An hour” (ae-n aw-er).
“An FBI …” (ae-n e-f-b-it-ay).
A similar exception happens with words that begin with vowels, such as “utopian” or “euro.” Both words begin with a vowel, but since we pronounce them as consonants, we use the article a instead. For example,
“A utopian” (ah y-uw-t-ow-p-iy-ah-n).
“A euro” (ah y-uw-r-ow).
A vs. an for abbreviations, acronyms, and initials
As a general rule of thumb, it’s best to proofread your writing aloud to check for tricky vowels and consonants. All words that begin with the letters H, U, E, O are suspect for frequent pronunciation changes but is especially true for initials, abbreviations, or acronyms.
To illustrate, let’s compare letters of the alphabet where we pronounce the first syllable as vowels against actual vowel letters.
Non-vowel letters with vowel sounds:
- F (eh-f or “eff”)
- H (ey-ch)
- L (el-l)
- M (eh-m)
- N (eh-n)
- R (aa-r)
- S (eh-s)
- X (eh-k-s)
Pronunciation of vowel letters:
- A (ah)
- E (iy)
- I (ay)
- O (ow)
- U (y-uw)
Although the letter U is a vowel, we don’t pronounce the letter as a vowel because the first syllable contains a y sound. The same is true of the non-vowels above, where the letters sound like a vowel, but they are not vowels in themselves. This is why certain abbreviations, acronyms, or initials follow a or an in a sentence.
- “A USC player.”
- “An MIT student.”
- “An M.D.”
- “An M.S.”
- “An NP.”
- “An FDIC.”
- “A USA.”
- “A UA.”
How to use a vs. an with adjectives
Now that we understand how to use articles for nouns, it’s time to learn the last rule for using a vs. an. If an adjective appears before a noun, the article should adhere to the adjective, not the noun. For example,
Correct: “Let’s watch an easy-going movie.”
Incorrect: “Let’s watch a easy-going movie.”
Correct: “He’s an objective reporter.”
Incorrect: “He’s a objective reporter.”
FAQ: Related to a vs. an
Does American English and British English affect the way we use a vs. an?
Yes! The difference between American and British English pronunciations is widely problematic for grammar students, but this is especially true for words that begin with the letter H. The most famous example is the word “historical.”
In the United States, we pronounce the word historical with a pronounced “h” sound, but British English speakers pronounce the word with a silent H instead. If you’re in Britain, people may expect you to write “an historical event” instead of “a historical event.”
The “soft-h” of English is also noteworthy thanks to the French language. Modern English maintains French pronunciation for terms like hors d’oeuvres (small appetizer), so the letter H is not pronounced. In this case, American English writers need to use an instead of a to indicate the correct pronunciation.
“I’d like to order an hors d’oeuvre,” or
“I can’t wait for the hors d’oeuvres.”
See how well you understand the proper form of “a” and “an” with the following multiple-choice questions.
- The articles “a” and “an” proceed ______________.
- Singular count nouns
- Singular noncount nouns
- Plural count nouns
- Plural noncount nouns
- We do not use “a” or “an” with ____________.
- Indefinite nouns
- Definite nouns
- Count nouns
- Singular nouns
- Which English initial requires the article “an” instead of “a”?
- The initial U
- The initial T
- The initial H
- The initial C
- “Would you like ______ hanger steak salad?”
- A and B
- “A lot of people use _____ writing style guide.”
- A and B
- “Articles, Determiners, and Quantifiers.” The Guide to Grammar and Writing, Capital Community College, n.d.
- “Determiners.” English Grammar, EF Education First Ltd., 2020.
- Jurafsky, Daniel, et al. “Articulatory Phonetics.” Speech and Language Processing, Stanford University, pp. 3, Dec 16, 2019.
- Hall, Barbara, et al. “Definite and Indefinite Articles.” College ESL Writers: Applied Grammar and Composing Strategies for Success, GALILEO, University System of Georgia, pp. 191, 2018.
- Lenzo, K. “The CMU Pronouncing Dictionary.” Speech at CMU, Carnegie Mellon University, n.d.“Using Articles.” Purdue Online Writing Lab, Purdue University, 2020.