Lot
Also known as: Standard Lot, Mini Lot, Micro Lot
A lot is the unit traders use to size positions. One standard lot equals 100,000 units of the base currency; a mini lot is 10,000 units; a micro lot is 1,000 units; a nano lot is 100 units.
Lot size determines the monetary value of every pip move on the position. Brokers express commissions, rebates, and swap charges per lot, so understanding lot sizing is essential before opening any trade.