In English there are two indefinite articles a and an. They are used before a noun to define it as something non-specific.
- I need to buy a new phone.
 (I am not talking about a specific phone.)
- Do you want a cup of coffee?
 (I am not thinking about a specific coffee.)
- This is my first time in an airplane.
 (This is the first time in any plane.)
- I want an apple for my lunch.
 (It can be any apple.)
Compare with the definite article.
Common mistakes with articles.





