In email terminology, “BBC” refers to “Blind Carbon Copy.” It is a feature that allows the sender to send an email to multiple recipients without revealing the email addresses of those recipients to each other. When recipients are added to the BCC field, they can see the email but will not know who else received it or see the other recipients’ email addresses. This is useful for maintaining privacy in mass communications or when sending emails to a group without disclosing everyone’s contact information.