Question

When you substitute a proper noun, replacing it with an ordinary noun, does that ordinary noun become a proper noun and require capitalization?

Answer 1

A proper noun is the name given to something to make it more specific (e.g., Johnathan, Ollie, London, Monday). Proper nouns are written with capital letters regardless of where they appear in a sentence. Proper nouns contrast with common nouns, which are the words for something (e.g., boy, dog, city, day).