What is a lot?

Lot is a standard unit of measurement for trading positions.

1 standard lot = 100,000 units of the base currency for currency pairs.
For other trading instruments:
1 standard lot of CFD on oil equals 1,000 barrels;
1 standard lot of XAUUSD equals 100 oz.;
1 standard lot of XAGUSD equals 5,000 oz.
You can check the lot size of other instruments here.

1 cent lot = 1,000 units of the base currency, i.e. 100 smaller than the standard lot.

In the R StocksTrader platform, trading volume is measured not in lots but in units of the base currency or the assets.