In order to confirm the identity of the person entering an account, a verification code is given to a different device. It's used for two-factor authentication.
Testnet
An alternative blockchain used by developers for testing.
Fiat
Fiat money, often known as fiat currency, is money that a government has recognized as legal tender and that it supports.
Altcoin
Altcoin is the term given to describe alternative digital assets, such as a coin or token that is not Bitcoin. This nomenclature comes from the idea that Bitcoin is the original cryptocurrency and that all others are then considered “alternate” or “alternative” coins.