What is Glen Plaid?
Glen plaid (or glenurquhart) is the genus and Prince of Wales plaid is a species. Glen-plaid thus refers only to the plaid pattern, whatever its color or scale. The particular rust-red, large-scale plaid described above is an old Scottish "district check" that was popularized by David, prince of Wales, in the 1920s. Thus it came to be known as the "Prince of Wales plaid." In later years, the terms came to be conflated, so that people would refer to any glen-plaid as a PoW plaid. But, technically, the true PoW plaid is the particular district check first popularized by the prince who became Edward VIII and then the duke of Windsor.