Yes, the compound noun 'nineteenth century' is a common noun, a general word for the one hundred years between 1801-1900; a general word for any point in the 1800s.
The word 'nineteenth century' also functions as an adjective.
common noun
Common
Common noun
common
Pea is a common noun, and peas is the plural...still a common noun.
A common noun.
Most definitely a common noun.
Camel is a common noun.
Th word tail is a common noun because the first letter of a proper noun is capitalized.
common
it is re@lly @ common noun
"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.