Lot is a measure of the order volume.
1 lot equals to 100 000 of the base currency.
Please, check how it looks in the Metatrader:
Here the volume size is 1.00 which means that you will trade this order with 1 lot.
Please, kindly be informed that the standard lot size is used for all the account types except Cent account.
Kind reminder: 1 lot on a “Cent” account = 0.01 standard lot.