Lapdog is a dog that is small enough to be held in the arms or lie comfortably on a person's lap. Lapdogs are not a specific breed, but is a generic term for a type of dog of small size and friendly disposition.

Lapdogs historically were kept in many societies around the world by individuals with leisure time, as docile companion animals with no working function. Genetic analysis reveals that lapdogs are among the earliest specific types of dogs to live with people. Today, most lapdog breeds fall into the Toy breed group.

-Wikipedia