Article

The demonstrative adjectives ‘a, an’ and ‘the’ are called articles. ‘A’ and ‘An’ are
called indefinite articles because they generalize a noun and show it as one out of
many. ‘A’ is used with words that begin with consonant sound while ‘An’ is used
with nouns that begin with vowel sounds.
Types of Articles
There are two articles in English language.
1. Indefinite article: a/an
2. Definite article:
The Definite Article: (the) The definite article "the" is used for a definite, specific
or particular noun.
Example: He bought the shirt.
The article “the” before the noun “shirt” in above sentence means that the shirt, he
bought, is a specific or particular shirt and not any shirt. Indefinite Article: (a/an) The indefinite article “a/an” is used for indefinite, nonspecific or non-particular (common) noun. Example. He bought a shirt. The article “a” before shirt in above sentence means that the shirt he bought is any shirt and not a specific shirt.

 Rules for Using Indefinite Article / (A/AN)
The article form “a” is used before a word (singular) beginning with a consonant,
or a vowel with a consonant sound. e.g. a book, a cat, a camera, a university, a
European. The article form “an” is used before a word (singular) beginning with a
vowel sound or consonant with vowel sound (or beginning with mute h). E.g. an
apple, an elephant, an umbrella, an hour.
1. Before a singular noun which is countable e.g.
He bought a book She is eating an apple.
2. Before a singular noun which refers to a class of things. e.g.
An orange is rich in vitamins.
3. Before a name of a profession e.g.
She wants to be a doctor.
He is an engineer.
4. For certain expressions of quantity e.g.
a lot of, a few, a couple, a dozen
5. For certain numbers. e.g.
a hundred, a thousand, a million
6. Before a singular, countable noun in exclamation. e.g.
What a beautiful flower! What a nice shirt!
7. Article a/an is not used before uncountable nouns e.g.
water, milk, sand etc.

 Rules for Using Definite Article (The) The article “the” can be used both before a singular and plural noun according to the following grammatical rules. e.g. the book, the books 1. Before the place, object or group of object which is unique or considered to
be unique and geographical region and points on globe. e.g. the earth, the
moon, the sky, the stars, the north pole, the equator
2. For a noun which becomes definite or particular because it is already
mentioned and is being mentioned a second time. e.g. The teacher helped a
student and the student became happy.
3. For a noun made specific or definite in a clause or a phrase. e.g. The old
lady, The girl with blue eyes, The boy that I saw, The nice red shirt
4. Before superlatives, and first, second, etc, and only e.g. The best day, The
only method, the second month,
5. Before a phrase composed of a proper and common noun e.g. The New
York city, The river Nile, The library of Congress
6. Before the names of organizations e.g. The Association of Chartered
Accountants, The World Health Organization
7. Before names of scientific principles, theories, laws etc. e.g. the
Pythagorean theorem, the laws of Newton, The Fahrenheit Scale. But no
article will be used for these names if written in forms like, Newton’s Law,
Dalton’s Law of Partial Pressures, Hook’s Law of Elasticity
8. Article “the” is not used for names of universities if written in forms like
Oxford University, Yale University, Columbia University. But article “the”
is used if names of university are written in forms like The University of
Oxford, The University of Yale, The University of Toronto.
9. Article “the” is not used for names of countries of places. e.g. New York,
America, Mexico, Japan, London. But article “the” is used for a name, if it
expresses a group of place, states, or land. e.g. The United States, The
Philippines, The Netherlands.