Usury (/'juʒ(ə)ɹi/, from the Medieval Latin usuria, "interest" or "excessive interest", from Latin usura "interest") was defined originally as charging a fee for the use of money. This usually meant interest on loans, although charging a fee for changing money (as at a bureau de change) is included in the original meaning. After moderate-interest loans were made more easily available usury became an accepted part of the business world in the early modern age. Today, the word has come to refer to the charging of unreasonable or relatively high rates of interest.
The pivotal change in the English-speaking world seems to have come with the permission to charge interest on lent money: particularly the Act 'In restraint of usury' of Henry VIII in England in 1545 (see book references).