The term "cc" in email stands for "carbon copy." It indicates that an email message is being copied to someone who is not the primary recipient. The term "bcc" stands for blind carbon copy and indicates that the email is being copied to someone without the knowledge of the primary recipient.
The term "carbon copy" was originally used in printed business letters and indicated the existence of a copy made using a specific type of paper known as carbon paper. The paper, which contained ink on the back, was used to make additional copies of documents created on typewriters. This technology was used before the advent of copying machines. At the bottom of a business letter, "cc" was used along with names to note the people receiving copies of the original letter.
Email, a way of exchanging electronic messages, has been in common use since about 1993. It is sent across the Internet or within internal corporate networks. Early email systems required that both the recipient and the sender of email be online simultaneously; as of 2014, users are not required to be online at the same time. Emails sent through the Internet include a header and body text. The header includes the email address of the person who sent the email, along with recipient addresses and the date and time that the message was sent.