A gunny sack, also known as a "gunny shoe", is an inexpensive bag made of hessian (burlap) usually formed from jute or other natural fibers, although modern sacks are often made from polypropylene; the "gunny" portion of the name ultimately descends from Tulu (Indian Language spoken in Mangalore) goni, "thread, fiber", by way of imperial British corruption of that word's descendants in later Indian languages. Reusable gunny sacks, typically holding about 45 kg, were traditionally, and to some extent still are, used for transporting grains, potatoes and other agricultural products. In many of those uses they have been largely replaced by non-reusable paper bags about half as big. Today they are also sometimes used as sandbags for erosion control. Gunny sacks are also popular in the traditional children's game of sack racing.
A gunny sack holds approximately 100 lb (45 kg) of potatoes. Even though gunny sacks are no longer used for that purpose, among Idaho farmers the common measurement unit of potatoes is still the "sack".