or an
Frequency: The word is one of the 700 most common words in English.
Note: 'A' or 'an' is the indefinite article. It is used at the beginning of noun groups which refer to only one person or thing. The form 'an' is used in front of words that begin with vowel sounds.
1.
You use a or an when you are referring to someone or something for the first time or when people may not know which particular person or thing you are talking about.
A waiter entered with a tray...
He started eating an apple...
Today you've got a new teacher taking you...
I manage a hotel.
DET: DET sing-n
2.
You use a or an when you are referring to any person or thing of a particular type and do not want to be specific.
I suggest you leave it to an expert...
Bring a sleeping bag...
I was waiting for a bus.
DET: DET sing-n
3.
You use a or an in front of an uncount noun when that noun follows an adjective, or when the noun is followed by words that describe it more fully.
There was a terrible sadness in her eyes...
DET: DET n-uncount with supp
4.
You use a or an in front of a mass noun when you want to refer to a single type or make of something.
Bollinger 'RD' is a rare, highly prized wine.
DET: DET n-mass
5.
You use a in quantifiers such as a lot, a little, and a bit.
I spend a lot on expensive jewelry and clothing...
I've come looking for a bit of advice.
DET: DET in quant
6.
You use a or an to refer to someone or something as a typical member of a group, class, or type.
Some parents believe a boy must learn to stand up and fight like a man.
DET: DET sing-n
7.
You use a or an in front of the names of days, months, or festivals when you are referring to one particular instance of that day, month, or festival.
The interview took place on a Friday afternoon...
DET: DET sing-n
8.
You use a or an when you are saying what someone is or what job they have.
I explained that I was an artist...
He was now a teacher and a respectable member of the community.
DET: DET sing-n
9.
You use a or an in front of the names of artists to refer to one individual painting or sculpture created by them.
Most people have very little difficulty in seeing why a Van Gogh is a work of genius.
DET: DET n-proper
10.
You use a or an instead of the number 'one', especially with words of measurement such as 'hundred', 'hour', and 'metre', and with fractions such as 'half', 'quarter', and 'third'.
...more than a thousand acres of land.
...a quarter of an hour...
DET: DET sing-n
11.
You use a or an in expressions such as eight hours a day to express a rate or ratio.
Prices start at ?13.95 a metre for printed cotton...
The helicopter can zip along at about 150 kilometres an hour.
DET: num DET sing-n