They are all the same meaning for a long bar of precious metal bullion. The names can be applied to various other metals, but normally refer to gold and silver bullion bars. A "Bar" can actually be the technical term used when referring to a standard Good Delivery bar. Commonly a "bar" refers to a shape of a bullion product which has its mass (weight) and purity stamped on the material. A 'Biscuit" is the name given to thinner cast bars, sometimes also referred to as wafers. An "Ingot" is a common description given to the shape of a piece of cast metal. It can refer to non-precious metals as well as bullion, and usually retains the shape of its original cast.