BCC, or "Blind Carbon Copy," is an email feature that allows the sender to include recipients without revealing their email addresses to others. When you add someone to the BCC field, they receive the email, but other recipients cannot see that they were included. This is useful for maintaining privacy and confidentiality among a group of recipients. Using BCC can help prevent reply-all chains and reduce clutter in inboxes. It is commonly used in professional settings, such as when sending newsletters or announcements to a large audience, ensuring that individual email addresses remain hidden from other recipients.