Yes, the noun owner is a common noun, a word for the owner of anything.
A proper noun is the name of a specific person, place, thing, or a title; for example:
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Yes, the noun 'landlord' (or 'landlady') is a common noun, a general word for any owner of rental property; a word for a person.
Common noun
Pea is a common noun, and peas is the plural...still a common noun.
A common noun.
Th word tail is a common noun because the first letter of a proper noun is capitalized.