Indefinite Articles: A and An | Definition, Useful Rules & Usage

Indefinite Article in English! An article is a word that modifies or describes the noun. It is used before the noun to show whether it refers to something specific or not.

Indefinite Article – Definition

What is an Indefinite Article?

“A” or “An” is used to talk about things which are not particular. Usually, these are things that haven’t been mentioned before or that the listener is unfamiliar with.

Indefinite Article – Rules

Indefinite articles ‘a/an’ are used as follows:

‘A’ is used before a word beginning with a consonant sound. Consonant letters in the English alphabet are B,C,D,F,G,H,J,K,L,M,N,P,Q,R,S,T,V,W,X,Y,Z.

  • For example: A boy, a cat, a dog, a fight, a gym, a horse, a joke, a kite, a lion, a mirror, a noise, a pin, a quilt, etc.

‘An’ is used before a word beginning with a vowel sound. Vowel letters in the English alphabet are A, E, I, O, U.

  • For example: An apple, an elephant, an idiot, an orange, an umbrella, etc.

Note here that the usage is on the basis of sound and not only the letter the word starts with.

For example:

“An hour”
“An honest man”
“A one eyed dog”

Do these seem wrong to you?

They’re not and the reason is that the ‘usage is on the basis of sound’. The words ‘hour’ and ‘honest’ both begin with a vowel sound, as the consonant ‘h’ is not pronounced. Similarly, the word ‘one’ begins with the consonant sound of ‘w’ and hence is written as ‘a one eyed dog’, not ‘an one eyed dog’.

Also, remember that we use “a” and “an” only before a singular noun. We can’t use “a” and “an” before a plural noun.

For example:

A book – correct
A books – incorrect
An egg – correct
An eggs – incorrect

Tips to remember the differences in a nutshell

# a + singular noun beginning with a consonant: a bag; a pen, etc.

# an + singular noun beginning with a vowel: an egg; an orphan, etc.

# a + singular noun beginning with a consonant sound: auser(sounds like ‘yoo-zer,’ i.e., gives a ‘y’ sound, so ‘a’ is used); a university; a European, etc.

# an + nouns starting with silent “h”: an hour; an honest man, etc.


These rules also apply in Acronyms.

For example:

  • He is a DU (Delhi University) student.
  • He is an IIT (Indian Institute of Technology) graduate.

The rule also applies when acronyms start with consonant letters but have vowel sounds.

For example:

  • She is an MBA (Master of Business Administration).

When/If the noun is modified by an adjective, the choice between “a” and “an” depends on the initial sound of the adjective that immediately follows the article.

For example:

  • a beautiful umbrella
  • an unusual situation
  • a European country (pronounced as ‘yer-o-pi-an,’ i.e., sounds like consonant ‘y’)

A/An is used to indicate membership in a group.

For example:

  • I am journalist. (I am a member of a large group of professionals known as journalists.)
  • She is an Indian. (She is a member of the people from India, known as Indians.)
  • A table to remember when or when not to use Articles

Indefinite Article –  Usage

‘A’/ ‘An’ is used


When mentioning something for the first time. I went for a movie.
When talking about something which belongs to a set of the same thing. This is a pen.
When talking about someone who belongs to a certain group. She is an engineer.
When talking about a certain kind of a thing. I’ve have made a great movie.
When wanting to say that someone is a certain kind of person. She is a shy girl.

Indefinite Article | Infographic

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Jeni Nelson
Jeni Nelson
1 month ago

I’ve have made needs to be corrected, please.

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