There are three articles: A, An, The. (They are also called determiners)
1. A or An is called the Indefinite Article, because it is used when we do not speak of any particular/definite person or thing:
1. He met a boy in the park.
2. It is an orange.
2. The is called the Definite Article, because it is used when we speak of some particular/definite person or thing:
1. This is the shirt that I bought yesterday.
2. He is the doctor who treated my brother.
3. Use of ‘A’
1. Words beginning with the sound of a consonant: a book, a player, a table.
2. Vowels having the sound of ‘yu’: a European, a useful thing, a utensil.
3. ‘O’ when it is sounded as ‘wa’: a one-rupee note, a one-way traffic
4. Use of ‘An’
Words beginning with a vowel sound: an apple, an umbrella, an hour, an honest girl, an honourable person.
Abbreviations starting with a vowel sound: an M.A., an MLA
5. Use of ‘The’
When we refer to some particular person or thing; as
This is the shirt I bought yesterday.
Call the boy sitting in the corner
The shawls of Kashmir are famous
When a singular Noun is used to indicate a whole class:
The elephant is a big animal
The dog is a faithful animal.