Overview
'A' and 'an' are indefinite articles used before singular countable nouns when introducing something for the first time or referring to one of many. 'The' is the definite article used when both speaker and listener know which specific thing is meant. No article (zero article) is used with plural and uncountable nouns in general statements.
a / an (Indefinite)
- aBefore consonant sounds: a book, a university
- anBefore vowel sounds: an apple, an hour
- UseFirst mention, one of many, jobs: She's a doctor.
the (Definite)
- Second mention or previously known: I saw the man again.
- Unique/only one: the sun, the president
- Superlatives: the best, the most expensive
- Specific: the car in my garage
Zero Article (no article)
- General plural/uncountable: Dogs are loyal. Water is essential.
- Most names: London, Ali, Mount Everest
- Most meals/sports/subjects: breakfast, football, science
When to use
First vs Second Mention
I saw a dog. The dog was barking.
Jobs
He's an engineer.
General Statements
Tigers are endangered.
Superlatives
It was the best film I'd seen.