A mackinaw coat is a type of heavyweight woolen coat that is perfect for cold weather. It is known for its thick, warm fabric, and it is typically worn as outerwear during the winter. The term mackinaw coat is derived from the Mackinaw woolen mills in Michigan, where the coat was first made. Some synonyms for the mackinaw coat include a plaid coat, a buffalo plaid jacket, a woolen jacket, a checkered coat or a tartan coat. These synonyms describe the same type of coat with different names, but they all refer to warm, heavy coats made from woolen fabric perfect for cold and snowy climates.