what is a private key

 A private key can also be called a mnemonic phrase, seed phrase or mnemonic seed.  It is a combination of 12 to 24 words in a specific order, to access your crypto on the blockchain.  It is the address to where your crypto is on the ledger.  Your private key is private and should not be shared with anyone, otherwise they can access your crypto.  Unlike a public key were you can share with anyone, because it is a place where people can send crypto to, but not actually access.