CC means Carbon copy. BCC, written usually below it, means "Blind Carbon Copy" . Actually, if you enter email addresses in CC , then all the recipients will be able to see the email addresses of the people who were sent the email. In BCC, this doesn't happen. (That's why its a good idea to use BCC instead, because people won't be very happy with you sharing their email addresses with people they may not know.)
Good email etiquettes include the usage of BCC over CC.
Feel free to ask again !