Gold ingots are basically gold bars that are cast from a mould rather than stamped like a gold coin. They tend to be rougher and thicker than stamped bars, often called biscuits, but still come in all weights from one gram up to a "London Good Delivery Bar" which is 12.5 kilograms or 400 ounces troy weight.
An ingot is a piece of relatively pure material, usually metal, that is cast into a shape suitable for further processing. In steelmaking, it is the first step among semi-finished casting products. Ingots usually require a second procedure of shaping, such as cold/hot working, cutting, or milling to produce a useful final product. Non-metallic and semiconductor materials prepared in bulk form may also be referred to as ingots, particularly when cast by mold based methods. Precious metal ingots can be used as currency (with or without being processed into other shapes), or as a currency reserve, as with gold bars.
There is no difference between types or shapes of bars, so whether it looks like a wafer, ingot or biscuit, we call them all bars.