Words are divided into different kinds or classes according to the work they do in a sentence. These kinds or classes are known as Parts of Speech. They are eight in number:
1. Noun
2. Pronoun
3. Verb
4. Adjective
5. Adverb
6. Preposition
7. Conjunction
8. Interjection.

What is noun?
1. Common Noun:
A common noun is a name given in common to every person or thing of the same class or kind. 

For example;
I write with a pen.
The student asked me a few questions.

2. Proper Noun
A proper noun is the name of a particular person or place.

For example:
Ramu is a wise fellow.
Patna lacks basic civic amenities.
Rule: Proper nouns are always written with a capital letter at the beginning.
Incorrect: Earlier the capital of india was in calcutta.
Correct: Earlier the capital of India was in Calcutta.
Rule: Proper nouns are sometimes used as common nouns.
Incorrect: LK Advani is today regarded as Sardar Patel of India.
Correct: LK Advani is today regarded as the Sardar Patel of India.
Rule: In this case proper nouns are always preceded by articles.
She is a Lata Mangeshkar.
Kalidas is the Shakespeare of India.


3. Collective Noun:
A Collective noun is the name of a group of persons or things. For example army, committee, crowd, fleet, flock, herd, jury, mob, parliament, team. 
Rule: A collective noun usually takes a singular verb and is substituted by a singular pronoun.
Incorrect: The jury were unanimous in their opinion.
Correct: The jury was unanimous in its opinion.
Rule: A collective noun takes a plural verb and is substituted by a plural pronoun when the individuals of which it is composed are thought of net behaving as a single unit.
Incorrect: The jury was divided in its opinions.
Correct: The jury were divided in their opinions.

4. Abstract Noun:
An abstract noun is usually the name of a quality, action or state considered apart from the object ( which is usually a common noun and often qualified by an adjective) to which it belongs. 

For example:
Innocence is integral to a child.
Love knows no bound.
5. Material Noun:
A material noun is the name of a material ( matter from which a thing is made). 

For example:
Cotton is the source of natural fibre.
Milk constitutes a nutritious food.
Rule: A material noun does not take an article (a, an, the) before it.
Incorrect: The tobacco is a cash crop.
Correct: Tobacco is a cash crop.
Rule: It takes articles when treated as common nouns.
Incorrect: They offered me glass of water.
Correct: They offered me a glass of water.


Numbers are of two kinds-
(1) Singular Number
(2) Plural Number

Generally while changing singular noun to plural we add s, es in the end.

For example

On the surface some nouns appear to be singular but in meaning they are treated as plural.

For example:
cattle, clergy, people, children, police, poultry
Incorrect: The peasantry has always stood as rockstars for the development of a country.
Correct: The peasantry have always stood as rockstars for the development of a country.
Some nouns look like plural but are always used as singular. For example,
Subjects - Mathematics, economics, physics, ethics, politics, classics.
Rule: When these subjects denote qualities or property, they are used in plural sense. For example,
Incorrect: His mathematics is weak.
Correct: His mathematics are weak.

Diseases - Rickets, AIDS, diabetes, mumps, measles. Some other nouns - News, gallows, summons, innings.

Some nouns are plural in form and in meaning, normally they are instruments or dress articles which have two parts and make a kind of pair. Do not use a/an before these nouns.

For example:
Spectacles, tongs, scissors, pincers, bellows, trousers, drawers, breaches, pants, knickers, pantaloons.

Certain other nouns - caves, riches (valuables), alms, funds, proceeds (profit), annals (record).
Incorrect : I bought a trousers yesterday.
Correct :I bought a pair of trousers yesterday.

Some nouns are always singular and used as singular only. 

For example 
Poetry, information, machinery, dust, furniture, dirt, traffic, money, music. Some nouns have one meaning in singular form and another in plural.

Quiz based on above concepts : 
When he returned (a)/ from America, he informed me (b)/ that he had come here (c)/ to do urgent work. (d)/ No error (e) 

I do my best (a)/ but I don’t understand (b)/ why I do not get expected (c)/ marks in the examination. (d)/ No error (e) 

 The pretty woman (a)/ sitting in the car (b)/ is the daughter of one of (c)/ the headman of the village. (d)/ No error (e) 

You will not be (a)/ allowed to go (b)/ anywhere else to (c)/ play outdoor games. (d)/ No error (e) 

The beautiful surrounding (a)/ of the palace (b)/ attracted a large number of (c)/ tourists coming from abroad. (d)/ No error (e) 

He did not know (a)/ that the headquarter (b)/ of the army (c)/ was in Delhi. (d)/ No error (e) 

Liberalisation of economy (a)/ has given birth to (b)/ many uncommon (c)/ phenomenon in the society.(d)/ No error (e) 

 Thousand of young (a)/ protesters were standing (b)/ at Jantar Mantar and (c)/ supporting Anna Hazare. (d)/ No error (e) 

 It is very difficult (a)/ to chase (b)/ a huge score in the (c)/ fourth inning. (d)/ No error (e) 

He gave me (a)/ a five-rupees note (b)/ and asked me to get (c)/ him a few cigarettes. (d)/ No error (e)

  1. e; No error 
2. e; No error 
3. d; Replace “headman” with “headmen” 
4. e; No error 
5. a; Replace “surrounding” with “surroundings” 
6. b; Replace “headquarter” with “headquarters” 
7. d; Replace “phenomenon” with “phenomena” 
8. a; Replace “thousand” with “thousands” 
9. d; Replace “inning” with “innings” 
10. b; Replace “rupees” with “rupee”