"Ours" is a possessive pronoun used to indicate ownership or belonging. It refers to something that is associated with the speaker and one or more other people. For example, in the sentence "This book is ours," the speaker is stating that the book belongs to them and at least one other person. In grammar, "ours" is part of a group of pronouns that include mine, yours, his, hers, and theirs. These pronouns help clarify relationships and ownership in communication, making it easier to understand who possesses what in a conversation.