"Yours" is a possessive pronoun used to indicate ownership or association. It refers to something that belongs to the person being addressed. For example, if someone says, "This book is yours," they mean that the book belongs to you. In written communication, "yours" can also be used in closing phrases, such as "Yours sincerely" or "Yours truly." These phrases express a polite and respectful way to end a letter or email, indicating a personal connection between the sender and the recipient.