The link I selected was just the first thing that came up when I looked for a citation. I knew as a matter of fact that it was the case before making the search, purely from having read the work of actual economists, who have for decades, and still to this day, use the word inflation to mean the increase in the supply of money.

It has always been used in this way by the Austrian school of economics. Most prominently, in Human Action[1] (1940), perhaps the best book on economics to exist. Mises makes a deliberate effort to encourage his readers to use the term properly. Here are some ways he describes inflation (1949 English translation):

"In the course of a monetary expansion (inflation) the first reaction is not only that the prices of some of them rise more quickly and more steeply than others. It may also occur that some fall at first as they are for the most part demanded by those groups whose interests are hurt."

"From this point of view the term inflation was applied to signify cash-induced changes resulting in a drop in purchasing power"

"The terms inflationism and deflationism, inflationist and deflationist, signify the political programs aiming at inflation and deflation in the sense of big cash-induced changes in purchasing power."

"What many people today call inflation or deflation is no longer the great increase or decrease in the supply of money, but its inexorable consequences, the general tendency toward a rise or a fall in commodity prices and wage rates. This innovation is by no means harmless. It plays an important role in fomenting the popular tendencies toward inflationism."

"The second mischief is that those engaged in futile and hopeless attempts to fight the inevitable consequences of inflation - the rise in prices - are disguising their endeavors as a fight against inflation. While merely fighting symptoms, they pretend to fight the root causes of the evil. Because they do not comprehend the causal relation between the increase in the quantity of money on the one hand and the rise in prices on the other, they practically make things worse."

"It is obvious that this new-fangled connotation of the terms inflation and deflation is utterly confusing and misleading and must be unconditionally rejected."

[1]:https://mises.org/library/human-action-0