Blind Carbon Copy (BCC)
Definition - What does Blind Carbon Copy (BCC) mean?
sends a copy of the email in transit to the defined email address(s) without letting any of the recipients know about it.
BCC is used when a sender wishes to send to multiple recipients without revealing the recipients to each other, or when the sender wants to send a copy of an email to other interested parties beyond the addressed recipient.
Techopedia explains Blind Carbon Copy (BCC)
The "To" field is used to add the directly addressed recipients, whereas the emails entered in the CC and BCC field will receive a copy of the email. Although the email addresses in the BCC field will also receive a copy of the email, those recipients' email addresses will not be visible to the recipients addressed in the "To" and "CC" fields, or to other recipients in the BCC field.