noun I
A [eɪ]
1) [C/U] the first letter of the English alphabet
2) A
[C/U] a mark that a teacher gives to a student's work to show that it is excellent
3) A
[U] a common BLOOD GROUP
from A to B — from one place to another[/ex]
A to ZBritish a book of maps showing all the roads in a particular town[/ex]
a */*/*/weak [ə] ; strong [eɪ]; an weak [ən] ; strong [æn] summary: A and an are indefinite articles. ■ A is used when the next word begins with a consonant. ■ An is used when the next word begins with a vowel sound.
1) used when you are mentioning a person or a thing for the first time
I have an idea.[/ex]
There's a concert on Sunday night.[/ex]
2) one
I have a sister and two brothers.[/ex]
a hundred/thousand/million[/ex]
3) used when you mean any person or thing of a particular type, but not a specific one
Have you got a car?[/ex]
Children must be accompanied by an adult.[/ex]
4) used when you say what job someone does
Ruth was a lawyer.[/ex]
I want to be an actor.[/ex]
5) used when you say what type someone or something belongs to
Maria is a Catholic.[/ex]
Greece has been a republic since 1973.[/ex]
6) used before a singular noun that represents every person or thing of a particular type
A dog needs regular exercise.[/ex]
A molecule consists of two or more atoms.[/ex]
7) used in phrases showing prices, rates, or speeds to mean ‘each' or ‘every'
Meetings are held four times a year (= four times every year).[/ex]
Tomatoes are £1.20 a kilo (= each kilo costs £1.20).[/ex]
90 miles an hour[/ex]
8) used in expressions of quantity such as ‘a lot', ‘a few', or ‘a great deal'
a lot of money[/ex]
a bit of luck[/ex]
We all appreciate a little encouragement.[/ex]
9) used before a noun that is formed from a verb and means a single action of that verb
Can I have a try?[/ex]
Let's take a walk round the garden.[/ex]

Dictionary for writing and speaking English. 2014.