The term 'heavy outer garment' can refer to two different types of clothing: an OVERCOAT and a greatcoat. An OVERCOAT is a long, heavy coat that is typically worn over other clothing for warmth and protection from the elements. A greatcoat is a similar type of coat, but it is usually longer and heavier than an OVERCOAT. Both garments are typically made of wool or other heavy fabrics and are designed to keep the wearer warm in cold weather.