Where the word comes from
Gunny comes from the Hindi and Sanskrit word goni, meaning a sack, so gunny bag literally translates to sack sack. It is the standard trade term in Bangladesh, India, Pakistan and across the GCC, and UAE and Gulf trading companies routinely list goods as gunny bags rather than hessian or burlap.
What a gunny bag is made of
A gunny bag is woven from jute, the natural bast fibre Bangladesh grows more of than anywhere on earth. The yarn is spun coarser than fine hessian, which gives the fabric its strength and the open, breathable weave that lets grain and produce release moisture in transit. Untreated jute is fully biodegradable; for food commodities the sack can be vegetable-oil treated (VOT) to make it odourless and food-contact safe.
What gunny bags are used for
Gunny bags are the default sack for agricultural bulk: rice, wheat, sugar, potatoes, onions, oilseeds, coffee, cocoa, cashew and animal feed. A standard gunny bag holds around 50 kg, with heavier sacking grades carrying up to 90 to 100 kg. The breathable weave is the reason gunny is preferred over plastic for grain that must not sweat or condense.
Gunny, hessian, burlap and sacking: the same fabric, different names
Buyers in different regions use different words for woven jute. Hessian is the UK and Commonwealth term, burlap is North American, gunny is South Asian, African and GCC, and sacking refers to the heavier, coarser grade. They describe the same family of woven jute fabric: sacking is heavier than hessian, and gunny usually means the raw-fibre sacking sack.
Why the term matters when you source
Use the buyer's own word in your enquiry. A GCC importer searching gunny bags and a UK buyer searching hessian sacks may want the identical product. Quoting in the local term, and stating weight in both oz and GSM, removes confusion and speeds the quote.