>>513346993 (OP)
usury, which is not synonymous with either “loan” or “interest”, although unsurprisingly, the modern definition has been corrupted and is incorrect. The American Heritage defines it thusly:
The practice of lending money and charging the borrower interest, especially at an exorbitant or illegally high rate.
An excessive or illegally high rate of interest charged on borrowed money.
Interest charged or paid on a loan.
Even in the precise wordings of the definition, we can see the ambiguity that is the red flag that a word spell has been cast. If both interest charged and paid on a loan are usury, then both the lender and the borrower are usurers. And if all interest paid is usury, then there is no need to bring the rate of interest into the equation at all, and any exorbitant, excessive, or illegal aspect is irrelevant.
Now, the history of economics, especially as recounted by Murray Rothbard, is essentially the history of relentlessly challenging the Catholic Church’s ban on usury. And in retrospect, it’s clear that this incoherence is the direct result of centuries of gradually chipping away at the concept through adulteration and expansion of the moral and legal permissibility of usury.