The indefinite article a/an is used before singular countable nouns and before adjectives followed by singular countable nouns.
Examples: A dog, a black cat, an orange shirt.
The indefinite article is used when we refer to something that is not specific.
Examples: I need to buy a pen. Buy the black pen.
It is used for professions and nationalities.
Example: He is an Icelander.
| The definite article is used | The definite article is not used |
| when talking about something specific. Example: Buy the black pen not the red one. | before the names of people, streets, cities, islands, continents and days. Examples: I do the shopping on Mondays. India is in Asia. |
| before names of rivers, seas, oceans and deserts. Examples: the Pacific Ocean, the Nile | before plural countable nouns when we refer to them in general. Example: I don't like spiders. |
| before groups of islands, mountain ranges and names of countries in the plural. Example: the Alps, the USA | before abstract nouns. Example: Love is important for everyone. |
| before family names, when we refer to the family as a whole Example: The Smiths are coming to dinner tomorrow. | before the words hospital, church, home, bed, school, work and prison, when they are used for the purpose for which they exist. Example: He broke into a bank and now he is in prison. |
| before musical instruments. Example: I play the violin. | before names of sports. Example: He plays football. |
| before names of hotels, cinemas and newspapers. Example: He is staying at the Ritz. | before by + means of transport. Example: He goes to work by bus. |
| before adjectives, when we refer to groups of people. Examples: the rich, the poor | before school subjects. Example: I like maths. |
