noun.
A medium-to-large dog of a breed originating in Scotland as a sheepdog, having a long narrow muzzle and either a long rough coat or a short smooth coat, depending on the variety.
The Century Dictionary and Cyclopedia
noun.
A sheep-dog; a variety of dog especially common in Scotland, much esteemed by shepherds and also by dog-fanciers.
the GNU version of the Collaborative International Dictionary of English
noun.
The Scotch shepherd dog. There are two breeds, the rough-haired and smooth-haired. It is remarkable for its intelligence, displayed especially in caring for flocks.