currencies are traded in specific amounts called lots. The standard size for a lot is 100,000 units.
There are also mini, micro, and nano lot sizes that are 10,000, 1,000, and 100 units respectively.

Different brokers may use different terms like ‘trading lots’ and or ‘position size’.
Here, evest uses the term "LOT". Basically it all amounts to the same thing – your trade size.