No, the word 'somebody' is NOT a noun. The word 'someone' is an indefinite pronoun, a word that takes the place of a noun for an unknown or unnamed person.
"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.
Proper nouns are names, so unless you know somebody or somewhere named Hoof, then it's a common noun.
It is a proper noun, because it is the name of a specific thing.
proper
Proper noun
Pencil proper or common noun
it's a common noun. a proper noun would be Spider-Man.
Proper noun or common noun
The noun cassette is a common noun.
a common noun?
Camel is a common noun.
The answer is proper noun. Examples of common noun and proper noun are: Proper noun: Mary Collins Common noun: monkey