Bcc stands for "blind carbon copy" and is a feature in email that allows the sender to conceal the person entered in the Bcc field from the other recipients. When an email is sent with Bcc, the primary and secondary recipients cannot see the tertiary recipients. Depending on email software, the tertiary recipients may only see their own email address in Bcc, or they may see the email addresses of all primary and secondary recipients but will not see other tertiary recipients. The Bcc feature is often used to prevent an accidental "Reply All" from sending a reply intended for only the originator of the message to the entire recipient list. It is also used to send a message to multiple parties with none of them knowing the other recipients. This can be accomplished by addressing a message to oneself (or leaving the To field empty) and filling in the actual intended recipients in the Bcc field. The Bcc feature can also be used to tighten the focus of an existing email correspondence by removing non-essential parties from the recipient list so that future reply-alls will not include them.