breed of terrier known for its gaiety and light-hearted devotion as a pet; loves to romp and play in snow; coat is white; outer layer is hard and straight and should be trimmed to distinctive form; inner layer is finer; ears are small and carried slightly erect; tail is shaped like stubby carrot; eyes are dark brown; adult stands 10–11 in. (25–28 cm) tall at shoulders and weighs 15–22 lbs (7–10 kg); originated in Scotland at time of King James I; also known as Roseneath terrier and Poltalloch terrier,