Ironically Tether, whose quantity appears to be determined by however much the small private entity that runs it decides to create, appears to be a much purer example of 'fiat' currency than most national currencies have been for most of the last half century (quantity determined in a decentralised manner by the balance of supply and demand for credit at a base interest rate a centralised body periodically updates to hit a [decentralised market-driven] fixed target rate of inflation)
Investopedia has:
>Fiat money is a government-issued currency that isn't backed by a commodity such as gold.
Tether fails the government-issued bit.
In what meaningful way is Tether not a fiat currency?
It is meaningful, because a large part of crypto culture seems to be based around hand-waving and selling you an underdog no-big-government empower-the-people story
The not government issued bit would become pretty meaningful if they get shut down or collapse. They are more like IOU notes for fiat currency - Tether owes you one US$.