blind carbon copy

In the context of email, blind carbon copy refers to the practice of sending a message to multiple recipients in such a way that what they receive does not contain the complete list of recipients. There are a number of reasons for using this feature:

To send a copy of your correspondence to a third party (for example, a colleague) when you don't want to let the recipient know that you're doing this (or when you don't want the recipient to know the third party's email address).
When sending an email to multiple recipients, you can hide their email addresses from each other. This is a sensible anti-spam precaution, because it avoids making a long list of email addresses available to all the recipients (which is what happens if you put everyone's address in the 'cc:' or 'to:' fields). For this reason, it often makes sense to use bcc: for mailing lists.

'Bcc' is also occasionally used to make certain types of spam email look more convincing - by hiding your email, the spammer may hope to trick you into believing you've accidentally received an email (about some amazing one-off bargain that will make you millions) that wasn't intended for you. The acronym bcc is often used to refer to blind carbon copy.

Blind Carbon Copy

See also