Great·coat or a heavy overcoat.
a heavy coat worn over clothes in winter
or OVERCOAT: a surtout/overcoat with flat collar toped with smaller collar raising to protect the face.
A heavy overcoat or great-coat.
large overcoat with double or triple shoulder capes attached.
A greatcoat, also known as a watchcoat, is a large overcoat typically made of leather designed for warmth and protection against the elements. It's collar and cuffs could be turned out to protect the face and hands from cold and rain, and the short cape around the shoulders provides extra warmth and repels rainwater (if made of a waterproof material). It was popular in the 15th Century as a military uniform and casual wear for the wealthy.