Page "Carbon copy" Paragraph 5

An alternative etymology is that " c :" was used for copy and " cc :" indicates the plural, just as " p ." means page and " pp. " means pages.

This alternative etymology explains the frequent usage of " c :" when only one recipient is listed, while " cc :" is used for two or more recipients of the copies.

This etymology can also why, even originally, " cc :" was used to list recipients who received typed copies and not necessarily carbon copies.