·noun Linen or cotton cloth such as sacks are made of; coarse cloth; anciently, a cloth or garment worn in mourning, distress, mortification, or penitence.
Cloth made of black goats' hair, coarse, rough, and thick, used for sacks, and also worn by mourners...
Easton's Bible Dictionary
cloth used in making sacks or bags, a coarse fabric, of a dark color, made of goat's hair, (Isaiah 5...
William Smith's Bible Dictionary