a/an — the indefinite article
a/an = one
The indefinite article a/an shows that we mean one thing or one person. It can't be used with the plural.
I see a man. = I see one man.
Can I have a cup of tea? = Can I have one cup of tea?
a million dollars = one million dollars
"a" before a consonant, "an" before a vowel
We put an before the vowels a / e / i / o / u. We put a before all other letters.
I've got an apricot and a pear.
I'll boil an egg and make a sandwich.
Peter's got an old typewriter and a bronze figurine.
Exceptions
a or an — depends on not how we spell but how we pronounce the next word.
- We use "a" before a silent "h"
an hour
an honourable man
- We use "a" if "u" sounds like [yu].
a university
a unicorn
a European country
What is it? Who is it?
We use the indefinite article a/an to say what a thing or a person is, what a thing or a person is like — when we speak about categories and characteristics.
Examples
This is a student.
"Windows" is an operating system.
A: What do you do? B: I'm an editor.
It's an interesting article, you should read it.
The moon isn't a planet.
She's wearing a black dress.