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.
Off-Chain
All network users can see on-chain transactions because they are recorded on the distributed ledger. Off-chain transactions, however, take place away from the blockchain network
Falling Knife
The term falling knife (also known as "Catching a Falling Knife" or "Catching the Bottoms") refers to the action of buying an asset which is rapidly declining in price.
Coin
Cryptocurrencies known as coins run on separate blockchains and are unrelated to other coins. Such a cryptocurrency's single unit is also known as a coin.