In forex, a "Lot" defines the trade size, or the number of currency units to be bought/sold in a trade. One Standard Lot is 100,000 units of the base currency.
Most brokers also allow trading with fractional lot sizes, down to 0.01, sometimes even less. Fractional lot sizes are categorized as mini lots (0.10), micro lots (0.01) and nano lots (0.001). Please refer to the image above to compare the lots and correspondent currency units.
