What is the primary role of 's' in the phrase "the dog's bark"?

The 's' in the phrase "the dog's bark" serves to indicate possession. In this context, it shows that the bark belongs to the dog, establishing a relationship between the noun "dog" and the noun "bark." This possessive form is a critical element in English grammar, as it clarifies ownership or association. For instance, in a similar phrase like "the cat's toy," the 's' indicates that the toy belongs to the cat. Understanding this possessive function is essential for conveying meaning accurately in sentences regarding ownership or relationship between objects and entities.