"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.
As a foreign proper noun, there is no consistent grammar across the Spanish world to deal with this. You will likely find that some people will say "los iPades" and others will say "los iPad".
"iPad" is a noun. You can tell it is a noun because it names a thing (I have an iPad), not an action (We iPadded the other day), a descriptive word (That shirt is so iPad on you), etc.
Pencil proper or common noun
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