Definition of articles

Definition of articles
English has two types of articles: definite (the) and indefinite (a, an.) The use of these articles depends mainly on whether you are referring to any member of a group, or to a specific member of a group:

1. Indefinite Articles: a and an
A and an signal that the noun modified is indefinite, referring to any member of a group. These indefinite articles are used with singular nouns when the noun is general; the corresponding indefinite quantity word some is used for plural general nouns. The rule is:
a + singular noun beginning with a consonant: a boy
an + singular noun beginning with a vowel: an elephant
a + singular noun beginning with a consonant sound: a user (sounds like 'yoo-zer,' i.e. begins with a consonant 'y' sound, so 'a' is used)
some + plural noun: some girls
If the noun is modified by an adjective, the choice between a and an depends on the initial sound of the adjective that immedately follows the article:
a broken egg
an unusual problem
a European country (sounds like 'yer-o-pi-an,' i.e. begins with consonant 'y' sound)
Note also that in English, the indefinite articles are used to indicate membership in a profession, nation, or religion.
I am a teacher.
Brian is an Irishman.
Seiko is a practicing Buddhist.
2. Definite Article: the
The definite article is used before singular and plural nouns when the noun is particular or specific. The signals that the noun is definite, that it refers to a particular member of a group. Compare the indefinite and definite articles in the following examples:

Indefinite (a or an)
Definite (the)
Singular
a dog (any dog)an apple (any apple)
the dog (that specific dog)the apple (that specific apple)
Plural
some dogs (any dogs)some apples (any apples)
the dogs (those specific dogs)the apples (those specific apples)

The is not used with noncountable nouns referring to something in a general sense:
[no article] Coffee is a popular drink.[no article] Japanese was his native language.[no article] Intelligence is difficult to quantify.
The is used with noncountable nouns that are made more specific by a limiting modifying phrase or clause:
The coffee in my cup is too hot to drink.The Japanese he speaks is often heard in the countryside.The intelligence of animals is variable but undeniable.
The is also used when a noun refers to something unique:
the White Housethe theory of relativitythe 1999 federal budget