Fiat money is government issued money in South Africa's case it will be the Rand, and for Nigeria it is Naira.
FIAT = ZAR, NGN, GBP, EUR, USD etc etc.
Crypto Currency = BTC, LTC, ETH etc. etc.
PROTIP: Not really a tip, but interesting fact that FIAT is the Latin word translated to "let it become", meant as an order or decree, a bit like the Satoshi White Paper......