What does C/C mean, when written on an envelope?

Question

My boyfriend is in the Air Force, and they're in Basic Military Training, so he sends letters...

I didn't bother writing the "C/C" part when sending mine, and I was wondering what it stands for. Thanks in advance.

So it looks like..

C/C Name

Address

City, State. Zip Code

Answer 1

The carbon copy notification tells everyone that they’re reading another person’s private mail.  It may not be addressed to you, but its coming to you.