Nouns are simply the names we give to everything around us, whether it be a person, an event, a place or an object, etc. Every particular name used to define something is a noun. E.g. : Amsterdam, Anita, Blackberry, Honesty, Waiter, etc.
The names given to a group of noun to identify them as a whole are called Collective Nouns. E.g.: pride of lions, gaggle of geese etc.
Nouns or pronouns can also modify themselves to show possession of another noun, usually by attaching 's' to the end of the noun. These nouns that show possession are called Possessive Nouns.
Sometimes nouns have different forms for different genders, although this practice has been largely abandoned by the people who prefer to use the same noun for both genders. For example - Actor (male) - Actress (female), but people nowadays refer to women who act as female actors rather than actresses.
Most nouns can be converted into plural forms by adding ‘-s’ or ‘-es’ at the end of the word. E.g.: box-boxes, cat-cats, echo-echoes , etc.
But some nouns require the last consonant to be modified before adding ‘-es’. For e.g.: the ‘Y’ in ‘city’ changes to ‘I’ to form cities, kitty to kitties and ‘f’ to ‘v’ in dwarf to dwarves, wharf to wharves, etc.
Some nouns become plurals irregularly by changing the entire word: mouse- mice, ox - oxen, etc.
You can learn more about Plurals here: How to make Plurals : Making Plurals-Easy Guide
Grammarians have divided nouns into different categories based on their use and purpose. Learning these divisions within the nouns will help in sentence construction and vocabulary. The different types of Nouns are -
These nouns are the names of specific people and places. These nouns also refer to the names of the days of weeks and months, and also the various names for religions, organizations, institutions, etc. Proper nouns basically refer to the names that are specific to that particular noun. These nouns are always capitalised as they need to be distinct from other nouns.
These are the nouns that are used to denote a general category of people, places or things. They are capitalized only when they are at the beginning of a sentence. Common Nouns don’t refer to something specific rather they are a general term used for every noun of a particular kind or type.
These nouns are the names of things that we cannot perceive through our five senses of touching, smelling, seeing, hearing and tasting. These nouns can also refer to medical conditions related to the mind and are also used to express thoughts.
The nouns that fall under this category are the ones that have both singular and plural forms. They can be counted either relatively or completely, and form plurals to associate with plural verbs in a sentence. They can also be expressed in numerical terms
These nouns are the exact opposite of Countable Nouns. These nouns are the names of things that cannot be counted and have only a singular form. These nouns use singular verbs in a sentence.