A noun is a part of speech that names a person [John], a place [home], a thing [dinner], or an idea or quality [justice].
When my children were young, and on noun review days, I had them point out and name items. Of course this was after a brief introduction to nouns. The introduction always included the topic "nouns" but did not always include the definition. I waited to see if they could define noun—to see if they could remember. Abstract nouns were handled a little more creatively.
Types of nouns: in bold
common: a man, the rivers, some collies
proper: Mr. Smith, in Tennessee, Mississippi River
collective: a flock, my family, the team [groups]
concrete: a table, my car, two shoes, white clouds
abstract: love, jealously, honor, sorrow [ideas, qualities]
compound: Some nouns have a name that is more than one word. My name for instance, Donna Young, is a proper noun with two words. "Buddy system" is a thing that is named with two words. Some things have two words put together to make their name such as walkway and basketball. In some compound nouns, the words are separated with hyphens: sister-in-law.
A noun usually changes form to indicate the plural and the possessive case.
subject, object of the verb, object of the preposition, predicate noun, adverbial [a noun that is functioning as an adverb], adjectival [a noun that is functioning as an adjective] See also Objects