abbr.carbon copy (used in business letters and emails to indicate a copy is sent to another person); carbon copy (used in business letters and emails to indicate a copy sent to another person); carbon copy (used in business letters and emails to indicate a copy is sent to another person); C++ source code file; carbon copy (used in business correspondence and emails to indicate a copy is sent to another person) v.to send a copy of a letter or email to someone other than the main recipient; to send a copy of a letter or email to someone other than the main recipient; to send a copy of a letter or email to someone other than the main recipient; to send a copy of a letter or email to someone other than the main recipient