Seigniorage
the income of whoever issues money: it collects interest on the reserves and pays the holders of its money nothing
In more detail
The income of whoever issues money: they receive interest on the reserves they have collected and pay nothing on their own obligations.
The concept is old: this is how mints and the first issuing banks earned their money.
In the academy “Seigniorage” is not a definition but an operation: you post it yourself and watch what it does to the balance sheet.