"Fiat" does not mean "real-world money" as any money you consider "real" is "real". "Fiat" refers to money not backed by something physical, and it is not a new term that appeared from the cryptocurrency space (as many believe).

The search trend, https://trends.google.com/trends/explore?date=all&q=Fiat%20M..., seems to be relative stable since start of collecting trend data (2004), with slightly increasing volume as we get closer to today, but generally stable.

More information: https://www.investopedia.com/terms/f/fiatmoney.asp