the word underground is a common noun but if used like Underground Railroad then it is proper
No, the compound noun 'underground river' is a common noun, a word for any underground river anywhere. A proper noun is the name of a person, a place, a thing, or a title. The River Fleet is an underground river that runs under London, UK. The River Fleet is a proper noun.
"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.
It is a proper noun, because it is the name of a specific thing.
Yes, "well" is a common noun when referring to a source of water found underground. It becomes a proper noun when used to refer to a specific location or landmark.
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.