The word ‘dog’ is a common noun. It refers to a general category of animals, rather than a specific name for one particular dog.
Common nouns are words that name general items, places, or people, such as ‘city,’ ‘car,’ or ‘teacher.’ They don’t specify which one. On the other hand, proper nouns are used to name specific individuals or entities, such as ‘Fido,’ ‘New York,’ or ‘Mr. Smith.’
When we say ‘dog,’ we could be talking about any dog, which is why it’s classified as a common noun. If we gave a specific name to a dog, like ‘Buddy’ or ‘Max,’ then that would be a proper noun. In summary, ‘dog’ is a common noun because it describes a general group rather than a specific individual.