Perhaps I have been misled.

I was under the impression that "inflation" and "deflation" referred not to an increase or decrease in the size of the monetary supply, but rather to an increase or decrease in the ratio of money to goods.

That is, if the economy and the money supply are both growing, it isn't "inflation" - that for it to be "inflation" requires money to be created faster than the valuable things upon which the money might be spent.