Noun is the first kind in Part of Speech. A noun is a word used as the name of the person, place or thing. The word "Thing" includes all objects that we see, hear, taste, touch, or smell and something that we can think of but cannot perceive (recognize) by sense.
1. Sita is a good girl.
2. Delhi is a State.
3. This book is for English reading.
In the above examples the given names sita, girl, delhi, book, english and state are names so we call them as nouns.