Indefinite Articles

The indefinite articles in English language are 'a/an'. They refer to a noun for the first time or a general noun when its identity is unknown.

Indefinite Articles in English Grammar

What Are Indefinite Articles?

Indefinite articles are used to introduce a noun that has not been previously mentioned or is not specific. They are used when the speaker is referring to a new or unspecified noun, or when the listener does not know which particular noun the speaker is referring to.

English Indefinite Articles

There are only two indefinite articles in English:

  • a
  • an

English indefinite articles 'a' and 'an' are used in many cases but in general, they are used with the following nouns:

  • Singular countable nouns: You can only use an indefinite article with a countable noun and it is a singular marker, so you cannot use it with uncountable or plural countable nouns
  • Common nouns: You can only use indefinite articles with common nouns. Using ‘a’ with proper nouns is very rare.

Before we discuss when and how to use indefinite articles, let us see the difference between 'a' and 'an'.

The Difference Between 'A' and 'An'

We use 'a' or 'an' depending on the initial sound of the noun that follows them:

  • If the noun starts with a consonant sound, use a
  • If the noun starts with a vowel sound, use an

a girl

The noun 'girl' begins with a constant 'g' sound so we use 'a'.

An orange

The noun 'orange' begins with a vowel 'o' sound so we use 'an'.

Keep in mind that not all words that begin with a vowel letter necessarily begin with a vowel sound and not all words that begin with a consonant letter necessarily begin with a consonant sound. Pay attention to the examples below:

An hour

The noun 'hour' starts with letter 'h' (a consonant) but 'h' here is not pronounced so the word starts with a vowel sound and gets 'an'.

A university

The noun 'university' starts with letter 'u' (a vowel) but 'u' here is not pronounced as a vowel so it starts with a consonant sound and gets 'a'.


With abbreviations, you should choose between 'a' and 'an' depending on how the first letter is pronounced. For example:

An F&A Union

F is a consonant, but begins with the sound /e/, so we say 'an F&A union'.

Indefinite Articles: Placement

As mentioned before, indefinite articles come before a noun or noun phrase and choosing 'a' or 'an' should be based on the sound that the noun phrase begins with. Take a look at the example below:

A well-equipped airplane

Here noun 'airplane' begins with a vowel sound but the whole noun phrase begins with 'w' (a consonant) so we should use 'a'.

An awesome airplane

Indefinite Articles: Uses

Referring to Something Unspecific

We can use indefinite articles to refer to something unspecific in general. Using an indefinite article indicates that the speaker does not have a specific thing in mind. Take a look at these examples:

I need a job.

Here by using 'a' the speakers indicates that it is not important what kind of a job.

I need the job.

Use of 'the' (a definite article) indicates that the speaker is talking about a specific job.

Using a description and an indefinite article can help to narrow down the scope of a noun and still remain unspecific. Look at these examples:

We are looking for a white car.

Using an indefinite article shows that any ‘white car’ would be good.

We are looking for the white car.

Here, by using a definite article 'the', speakers indicate that they are looking for a specific car which is white.

Referring to Something Unknown

using the indefinite article 'an' in a sentence

Indefinite articles are used to refer to an unknown person or thing. In these cases, the speaker is referring to a specific noun, but because it is unknown or not previously mentioned, an indefinite article is used. Take a look at these examples:

He saw a man in the store.

Here, although we are talking about a specific man, because the speaker does not know the identity of that man, an indefinite article was used.

When using an indefinite article to refer to an unknown or unspecified person or thing, it is typically used only in the first sentence or instance of reference. In subsequent sentences or instances of reference, a definite article is generally used instead. This is because once the noun has been introduced with an indefinite article, it is no longer unknown or unspecified. Take a look at this example:

He saw a man in the store. The man pulled a gun and killed the owner.

By using 'the man' in the second sentence we indicate that we are talking about the same man. If we use an indefinite pronoun in the second sentence, it would be assumed that they are two different men.

Referring to a Member of a Group with the Same Features

Indefinite articles are used to refer to a particular member of a group or class, such as a profession, nationality, religion, etc. Here are some examples:

He always wanted to be a singer.

'A' is used to refer to a job (singer).

I'm a Protestant.

'A' is used to refer to a religion (Protestant).

Are you an Irishman or an Englishman?

'A' is used to refer to a nationality (being English or Irish).

Referring to a Whole Group

Indefinite articles can be used to refer to a specific group or category or to all members or things in a group in a general sense. Take a look at the examples:

An elephant is a mighty animal.

Here 'an elephant' is referring to all elephants or elephants as a group. And 'a mighty animal' is a noun phrase in which ‘a’ is preceding the adjective 'mighty'.

A flower is beautiful.

In this sentence, 'a flower' is representing all flowers.

Before Days of the Week on Unspecific Dates

When we are referring to a particular day of the week on an unspecific date, we can use the indefinite article 'a' with the name of the day of the week. Let us see some examples:

I met her on a Friday.

Here, Friday refers to a day of the week but without specifying a specific date.

I'll eventually go there on a Sunday.

Before Uncountable Nouns

As mentioned earlier, uncountable nouns cannot normally take a/an. However, if the noun has an adjective before it or a modifying phrase following it, we can use an indefinite article before the noun phrase.

A dreamless deep sleep

'Sleep' is an uncountable noun, but because it has adjectives before it, we can use indefinite article.

An amazing adventurous childhood

Talking about Price, Amount, etc.

Indefinite articles are also used to talk about prices, amounts, quantities, and rates. For example:

This type of rice cost 50$ a kilo.

Used in Some Numbers

'A' is used before some numbers to mean 'one'. For example:

One hundred = A hundred

One thousand = A thousand

Before Jobs and Professions

When we talk about a person’s job, we use the article 'a'. For example:

She’s a gardener.

He’s an ambulance driver.


'Indefinite articles' are used to narrow what we talk about and still make us have an unspecific purpose. By indefinite articles we mean (a/an). So, What are their differences?

the article 'a' use 'a' before consonant sounds He has a weird habit.
the article 'an' use 'an' before vowel sounds They left about an hour ago.

Indefinite articles have many functions. Some of them are:

  1. Referring to something unknown
  2. Referring to a member of a group with same traits and features
  3. Referring to a whole group
  4. Before days of the week or unspecific dates
  5. Before uncountable nouns
  6. Talking about prices, amounts etc.
  7. Used in some numbers to mean 'one'

As it was mentioned earlier, indefinite articles are used before singular countable nouns which makes it clear that we cannot use them with uncountable nouns. But there is an exception. We can use indefinite articles before an uncountable noun that has an adjective before it.


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