In Russian grammar, possessive pronouns are used to show ownership or belonging. They agree in gender, number, and case with the noun they modify, and have different forms depending on the person (first, second, or third) and the gender of the noun. For example, “мой” (my) in masculine form, “моя” in feminine form, “моё” in neuter form, and so on. As possessive pronouns are essential for expressing possession and building a more complex sentence structure in Russian, mastering them is crucial for learning the language.