"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.
No, "harmony" is not a proper noun. It is a common noun that refers to the combination of different musical notes played or sung together to create a pleasing sound.
Pencil proper or common noun
The word boy is a common noun; the proper noun would be the name of the boy or the word boy used as a name or a title, such as entertainer Boy George, the book/movie title 'The Boy in the Striped Pyjamas'.
proper noun
Exxon is a proper noun
Yes, the word 'Ali' is a proper noun, the name of a person.A proper noun is the name or title of a specific person, place, or thing.A proper noun is always capitalized.
proper noun
Proper noun
It is a proper noun, because it is the name of a specific thing.
what is trix
Proper noun or common noun