common noun vs noun

common noun and noun both are nouns.

Word	Noun	Adjective	Verb	Adverb
common noun	Yes	No	No	No
noun	Yes	No	No	No

As nouns, noun is a hypernym of common noun; that is, noun is a word with a broader meaning than common noun:

common noun: a noun that denotes any or all members of a class
noun: a content word that can be used to refer to a person, place, thing, quality, or action

common noun (noun)	noun (noun)
a noun that denotes any or all members of a class	a content word that can be used to refer to a person, place, thing, quality, or action
	the word class that can serve as the subject or object of a verb, the object of a preposition, or in apposition