‘Peg-in’ means wrapping up your tokens in the Binance Chain/Binance Smart Chain ecosystem. It allows you to use the tokens from different blockchains on the Binance Chain/Binance Smart Chain by locking up the native tokens and issuing the wrapped tokens corresponding to them. These wrapped tokens are called  Pegged tokens and have 100% backed value to their native token.  Converting the Pegged tokens to their native token is something that refers to as ‘Peg-out’. It means to take tokens out of the Binance ecosystem. You can Peg-in and peg-out tokens by using Binance Bridge.