Cc
Cc is an abbreviation for carbon copy. If you add a recipient's name to this box in a message, a copy of the message is sent to that recipient, and the recipient's name is visible to other recipients of the message.
Bcc
Bcc is an abbreviation for blind carbon copy. If you add a recipient's name to this box in a message, a copy of the message is sent to that recipient, and the recipient's name is not visible to other recipients of the message. If the Bcc box isn't visible when you create a new message, you can add it.