It's not easy to describe a noun. In simple terms, nouns are "things" (and verbs are "actions"). Like food. Food (n) is something you eat (v). Or happiness. Happiness (n) is something you want (v). Or human being. A human being (n) is something you are (v).
These pages explain more about the grammar of nouns and offer example sentences, quizzes and songs.
Countable and uncountable nouns. Why do some nouns have no plural?
dog/dogs, rice, hair(s)
Your name is a "proper noun". Do we say "Atlantic Ocean" or "the Atlantic Ocean"? Should I write "february" or "February"?
Shirley, Mr Jeckyll, Thailand, April, Sony
Adding 's or ' to show possession or ownership
John's car, my parents' house
Noun as Adjective
Sometimes we use a noun to describe another noun. In that case, the first noun is "acting as" an adjective.
love story, tooth-brush, bathroom
A compound noun is a noun that is made with two or more words.
tennis shoe, six-pack, bedroom