Bcc is an abbreviation of "blind carbon copy" whose meaning in Portuguese is "Hidden carbon copy". Bcc or Bcc (Blind copy) is a term that arises in the context of sending email, when the user intends to send the same message to multiple recipients without them seeing the email addresses listed in the message.
Carbon copy is achieved using carbon paper, which has a layer of ink on one side of the paper. When the opposite side is pressed, ink is transferred creating a copy. The term Bcc is sometimes referred to as "Blind Courtesy Copy" (free copy).
It is a very useful option when you want to forward a message to several contacts and hide all addresses so that they are not disclosed. It's a safe way to avoid spam because the emails will not be visible to be used by spammers. This option is also part of the "Netiquette" rules, a set of etiquette rules that guide users' behavior on the Internet.
When you want to send a copy of the same email to other recipients without hiding the email addresses, you must use the "Cc" (With copy) field.