Nouns refer to persons, animals, places, things, ideas, or events, etc. Nouns encompass most of the words of a language.
Noun can be a/an -  
o    Person – a name for a person: - Max, Julie, Catherine, Michel, Bob, etc.
o    Animal – a name for an animal: - dog, cat, cow, kangaroo, etc.
o    Place – a name for a place: - London, Australia, Canada, Mumbai, etc.
o    Thing – a name for a thing: - bat, ball, chair, door, house, computer, etc.
o    Idea – A name for an idea: - devotion, superstition, happiness, excitement, etc.
Examples of Noun in sentence
Different Types of Noun:
·         Proper Noun
·         Common Noun
·         Abstract Noun
·         Concrete Noun
·         Countable Noun
·         Non-countable Noun
·         Collective Noun
·         Compound Noun
Proper Noun:
A proper noun is a name which refers only to a single person, place, or thing and there is no common name for it. In written English, a proper noun always begins with capital letters.
Example: Melbourne (it refers to only one particular city), Steve (refers to a particular person),
Australia (there is no other country named Australia; this name is fixed for only one country).
More Examples of Proper Noun
Common Noun:
A common noun is a name for something which is common for many things, person, or places. It encompasses a particular type of things, person, or places.
Example: Country (it can refer to any country, nothing in particular), city (it can refer to any city like Melbourne, Mumbai, Toronto, etc. but nothing in particular).
So, a common noun is a word that indicates a person, place, thing, etc. In general and a proper noun is a specific one of those.
More Examples of Common Noun
Abstract Noun:
An abstract noun is a word for something that cannot be seen but is there. It has no physical existence. Generally, it refers to ideas, qualities, and conditions.
Example: Truth, lies, happiness, sorrow, time, friendship, humor, patriotism, etc.
Abstract Noun examples in sentences
Concrete Noun:
A concrete noun is the exact opposite of abstract noun. It refers to the things we see and have physical existence.
Example: Chair, table, bat, ball, water, money, sugar, etc.
Countable Noun:
The nouns that can be counted are called countable nouns. Countable nouns can take an article: a, an, the.
Example: Chair, table, bat, ball, etc. (you can say 1 chair, 2 chairs, 3 chairs – so chairs are countable)
Countable Noun examples in sentences
Non-countable Noun:
The nouns that cannot be counted are called non-countable nouns.
Example: Water, sugar, oil, salt, etc. (you cannot say “1 water, 2 water, 3 water” because water is not countable)
Abstract nouns and proper nouns are always non-countable nouns, but common nouns and concrete nouns can be both count and non-count nouns.
Non-countable Noun examples in sentences
Collective Noun:
A collective noun is a word for a group of things, people, or animals, etc.
Example: family, team, jury, cattle, etc.
Collective nouns can be both plural and singular. However, Americans prefer to use collective nouns as singular, but both of the uses are correct in other parts of the world.
Compound Noun:
Sometimes two or three nouns appear together, or even with other parts of speech, and create idiomatic compound nouns. Idiomatic means that those nouns behave as a unit and, to a lesser or greater degree, amount to more than the sum of their parts.
Example: six-pack, five-year-old, and son-in-law, snowball, mailbox, etc.
Functions of Nouns
Nouns can be used as a subject, a direct object, and an indirect object of a verb; as an object of a preposition; and as an adverb or adjective in sentences. Nouns can also show possession.
Subject: The company is doing great. Roses are the flowers of love.
Direct object: I finally bought a new mobile.
Indirect object: Max gave Carol another chocolate.
Object of preposition: Roses are the flowers of love.
Adverb: The train leaves today.
Adjective: The office building faces the mall.
Possession: The lion’s cage is dangerous. My brother’s daughter is adorable.