Final answer:
A blind carbon copy (Bcc) is used in email and written correspondence to send a document to multiple recipients without revealing the identities of the other recipients to each other, ensuring privacy and confidentiality.
Step-by-step explanation:
The document you're referring to is known as a blind carbon copy (Bcc). This feature in email and written correspondence allows the sender to conceal the full list of recipients from each individual recipient. The term blind refers to the fact that the other recipients will not know who else has received the message, providing a level of privacy and confidentiality for communication that involves multiple parties. Historically, the practice stems from the necessity to send a single document to multiple parties without disclosing their identities to each other, pertinent in both business and personal communications.