Note that nouns can fit into more than one of these categories. For example, the word cat is a common, concrete, countable, singular noun. • Common: These name general, nonspecific people, places, things, or ideas. They start with a lowercase letter unless they begin a sentence.
http://www.english-grammar-revolution.com/what-is-a-noun.html
noun modifiers. back next. We often use two nouns together to show that one thing is a part of something else: the village church; the car door; the kitchen window; the chair leg; my coat pocket; London residents.
https://learnenglish.britishcouncil.org/en/english-grammar/adjectives/noun-modifiers
A noun is the name of a person, place, thing, or idea. Whatever exists, we assume, can be named, and that name is a noun. A proper noun, which names a specific person, place, or thing (Carlos, Queen Marguerite, Middle East, Jerusalem, Malaysia, Presbyterianism, God, Spanish, Buddhism, the Republican Party), is almost always capitalized.
http://grammar.ccc.commnet.edu/GRAMMAR/nouns.htm
Definition: A noun is a word used to refer to people, animals, objects, substances, states, events and feelings. Nouns can be a subject or an object of a verb, can be modified by an adjective and can take an article or determiner. For example:
http://www.englishlanguageguide.com/grammar/noun.asp
(with Examples) A noun clause is a clause that plays the role of a noun. For example (noun clauses shaded): I like what I see. I know that the tide is turning. I've met the man who won the lottery.
http://www.grammar-monster.com/glossary/noun_clauses.htm
What Is Grammar? People often think of grammar as a matter of arbitrary pronouncements (defining 'good' and. 'bad' language), usually negative ones like “There is no such word as ain't” or “Never end a. sentence with a preposition.” Linguists are not very interested in this sort of bossiness. (sometimes called prescriptivism).
http://www.linguisticsociety.org/sites/default/files/Grammar.pdf
Definition: A noun is a word used to refer to people, animals, objects, substances, states, events and feelings. Nouns can be a subject or an object of a verb, can be modified by an adjective and can take an article or determiner. Nouns also denote abstract and intangible concepts.
http://www.englishlanguageguide.com/grammar/noun.asp
A Noun Phrase, frequently a noun accompanied by modifiers, is a group of related words acting as a noun: the oil depletion allowance; the abnormal, hideously enlarged nose. There is a separate section on word combinations that become Compound Nouns — such as daughter-in-law, half-moon, and stick-in-the-mud.
http://grammar.ccc.commnet.edu/GRAMMAR/nouns.htm
Nouns are words that name people, places, things, or ideas. They are not actually people, places, things, or ideas. After teaching grammar for some time, I was surprised at how many of my students weren't really clear on the whole word thing. Allow me to make this clear.
http://www.english-grammar-revolution.com/what-is-a-noun.html
We can use noun modifiers to show what something is made of: a gold watch; a leather purse; a metal box. We often use noun modifiers with nouns ending in -er and -ing: an office worker; a jewellery maker; a potato peeler; a shopping list; a swimming lesson; a walking holiday. We use measurements, age or value as noun modifiers:
https://learnenglish.britishcouncil.org/en/english-grammar/adjectives/noun-modifiers
what is a noun grammar
A noun grammar is a word used to refer to people, animals, objects, substances, states, events and feelings. A noun is a word in grammar, used to refer to people, animals, objects, substances, states, events and feelings. In grammar a noun  is a word used to refer to people, animals, objects, substances, states, events, and feelings