Indefinite Article

The indefinite articles in the English language are a and an. While the article ‘a’ is used before a word beginning with a consonant sound, the article ‘an’ is used before a word beginning with a vowel sound.

The indefinite article ‘a/an’ is used before a noun in the following cases:

  1. To convey the numerical sense of one, e.g.,
    This student has a pen  
  2. To talk about a single non-specific thing, e.g.,
    When the girl was at the zoo, she saw an elephant
  3. Before a noun representing a whole class, e.g.,
    A teacher must have patience.
  4. To talk about a particular person or thing when the listener or reader does not know which person or thing is meant, e.g.,
    We live in a big city.
  5. Instead of the word ‘per’, e.g.,
    Cheetahs can run 60 miles an
  6. To talk about some health conditions or illnesses including most pains, aches and attacks such as a cold, a heart attack, a stroke, a tumor, a sore throat, a toothache, a headache, e.g.,
    She has a sore throat. The sore throat made it hard to talk.
    ** Important** Both definite and indefinite articles can be used to talk about these health conditions.


For more information on the use of the indefinite articles a/an, please refer to the following sources: