What is a "mackinaw coat"?

A Mackinaw coat is a heavy, woolen coat originally made of a thick, water-repellent woolen material and typically features a plaid pattern. It is designed to keep the wearer warm in cold weather and is often worn as an outer layer in outdoor activities such as hunting, fishing, or camping. The coat typically has a boxy cut, a button or zipper front, and a high collar to protect the neck from the wind and cold. The Mackinaw coat is named after Mackinac Island in Michigan, USA, where the woolen material used to make the coat was first produced.