Our is a pronoun and belongs to an adjective pronoun. Adjective pronouns are a kind of pronouns used as attributes in sentences, which are often placed before modified nouns to modify the nature, characteristics or attributes of nouns.

For example:

That's our house. That's our house. )

I will take our dog to the park. I will take our dog to the park. )

Pronouns can be divided into four parts of speech: subject pronouns, object pronouns, attributive pronouns and adverbial pronouns. The subject pronoun is used in the subject position, the object pronoun is used in the object position, the attribute pronoun is used in the attribute position, and the adverbial pronoun is used in the adverbial position. For example:

She is a kind person. (She is a kind person. )

She is a subject pronoun, used in the subject position.

I will take my book to the library. I will take my book to the library. )

My is an attributive pronoun and is used as a modifier in a book.

He gave me his pen. He gave me his pen.