Well...actually, a fiat currency is one declared and issued by the state as legal tender. It's typically not redeemable for anything else, as a gold-backed one (USD from 1944 to Nixon) is.
And really, a currency like gold is valuable because it has a fixed supply and is universally accepted. Bitcoin has a fixed supply and is rapidly moving towards universal acceptance. It's totally different when a government chooses to make a dollar worth approximately X much and then prints 85 billion of them per month.
So, yeah, gold isn't a fiat currency. And Bitcoin isn't one either.
And really, a currency like gold is valuable because it has a fixed supply and is universally accepted. Bitcoin has a fixed supply and is rapidly moving towards universal acceptance. It's totally different when a government chooses to make a dollar worth approximately X much and then prints 85 billion of them per month.
So, yeah, gold isn't a fiat currency. And Bitcoin isn't one either.