In my opinion, I do not think jackg is right, or may I am the person that is wrong. Like I commented also above, the passphrase that I know are:

• The BIP38 passphrase needed to encrypt paper wallet
• The mnenomic passphrase which is also regarded as extended word

I remembered when I was using Coinomi (close source not recommended), I set a password which is always require before broadcasting a transaction, but, this is not called passphrase but password. I have been using Electrum quite awhile now, I make transactions without this type of password needed while electrum also do not support BIP38 passphrase which can be enabled using paper wallet to encrypt the private key. So, it is clear enough that the OP is asking about mnemonic which you perfect answered.