Yes, the word 'then' does function as a noun, as well as an adverb and an adjective.
The noun 'then' is a word for 'that time or moment'. Example uses:
noun: The essay is due on Friday and I have a lot of research to do before then.
adverb: I finished my homework then went to bed.
adjective: I met my husband, then a student, at a bookstore.
Proper noun
"night" is a noun
The noun cassette is a common noun.
No, the noun shelf is a common noun, a word for any shelf.
A noun A noun
The word 'noun' is not a verb. The word 'noun' is a noun, a word for a thing.
Proper noun
Concrete noun
The noun "noun" is a singular, common, concrete noun, a word for a thing.
Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.Yes, its a noun in the plural.
Most definitely a common noun.
The word astrologist is a noun. It is a common noun.
"night" is a noun
The noun cassette is a common noun.
it is not a noun; troop is a noun. Troop is a common noun.
As given, it is a proper noun, as it is the name of a person. Both words begin with a Capital Letter ; 'Charley Reynolds'. Similarly, The President of the United States of America is 'Mr. Donald Trump'. Note the use of capital letters.
Yes, the word 'noun' is a noun, a word for a thing.