puff. 1  a short, quick blast, as of wind or breath. 2  an abrupt emission of air, smoke, vapor, etc. 3  an act of inhaling and exhaling, as on a cigarette or pipe; whiff. 4  the sound of an abrupt emission of air, vapor, etc. 5  a small quantity of vapor, smoke, etc., emitted at one blast. 6  an inflated or distended part of a thing; swelling; protuberance.
The Shetland Sheepdog is related to the Rough Collie, both dogs descended from Border Collies that inhabited Scotland. The Border Collies were brought to the Scottish island of Shetland and crossed with the Icelandic Yakkin, a small island dog which is now extinct. By 1700, the Sheltie was completely developed.
U.S. breeders imported Shelties from England until the 1950's, but by that time, American and British Shelties had begun to diverge greatly in type and size. Today, almost all Shetland Sheepdogs in the U.S. are descended from dogs that were imported from England between World Wars I and II.