Article

what is the definition of article? An article is a word that is used before a noun to show whether the noun refers to something specific or not.

 The English language uses three words as articles, they are:

1.  “a” before indefinite singular nouns starting with a consonant sound
2.   “an” before indefinite singular nouns starting with a vowel sound
3.  “the” before definite nouns.

So, the number of specific rules and exceptions regarding usage can frustrate students of English as a second language, but most uses of articles under a few fundamental rules. Therefore, to make sure that if we want to make the article correct we have to follow the rules above.

 

Examples :

"I need a chair."

In the sentence above we find the article "a". It shows us that the speaker does not need a specific chair. He can have any chair.

"I want an apple."

In the sentence above we find the article "an." It shows us that the speaker does not want a specific apple. He can have any apple.

"I want the red apple."

In the sentence above we find the article "the." It shows us that the speaker wants a specific apple.

In English, there are two kinds of grammar articles.

The Definite Article
(For example: the box)

 

 

"Definite" means "clear,abvious"

The definite article tells us that the noun is specific. The speaker talks about a particular (or known) thing.

The definite article in English is "the."

Examples:

"The car I bought broke down."
"He has a son and a daughter. The daughter is a doctor."
"The actors were really good."
"I remember the day we first met."

"The" can be used before both singular and plural nouns.

Examples:

"The flower he gave her was very beautiful."
"The flowers on the table are nice."

The Indefinite Article
(For example: a box)

 

 

"In-" means "not," and "definite" means "clear, obvious."

"Indefinite" means "not clear, not exact."

The indefinite article tells us that the noun is not specific. The speaker talks about any one of that type of thing.

The indefinite articles in English are "a" and "an."

Examples:

"I need a pen."
(The speaker doesn't tell us which pen he needs. He simply needs a pen, any pen.)

"Lisa wants to see a movie."
(The speaker doesn't tell us which movie Lisa wants to see. She wants to see some movie.)

"Joe has a car."
(The speaker doesn't tell us which car Joe has. He has some car.)

"She is a dancer."
(She dances for a living.)

What is the difference between "a" and "an"?

"A" and "an" have the same meaning.

We use "a" before a consonant sound

Examples:
a dog
a building
a country
a professor
a university

We use "an" before a vowel sound
Examples:
an apple
an umbrella
an eye
an hour

Important!

We use "a" and "an" only before a singular noun. We can't use "a" and "an" before a plural noun.

Examples:

Correct: a car.
Incorrect: a cars.

Correct: an orange.
Incorrect: a oranges.

What is the difference between "a" and "the"?
"The" is used to talk about specific or known things. These are usually things that have been mentioned before or that the listener is familiar with.

"A" (or "an") is used to talk about things which are not specific. These are usually things that haven't been mentioned before or that the listener is unfamiliar with.

Let's say I tell you: "I went to see a doctor last week."
Explanation: I went to see some doctor. I didn't mention him before, and you are not familiar with him. Another option is that it is not important who he is. So I use the word "a".

Then I say: "The doctor said I should get more rest."
Now you already know which doctor I am referring to. I am referring to the doctor I went to see. So I use the word "the."

Source :

http://www.really-learn-english.com/english-grammar-articles.html

http://www.ehow.com/list_6385918_functions-article-english-grammar_.html