An Acronym with many meanings:

Carbon Copy

An recipient who is sent a copy of an Email, but is not the primary addressee and is usually not expected to reply. The primary addressee are aware that the carbon copy recipient has received a copy of the message. The terminology goes back to the days when office communication was typewritten and carbon paper was used to produce several copies simulatanously.

Compare BCC.

C Compiler

In Unix tradition, the C Compiler binary is called cc, and among the MakefileVariables, there's one called CC which stores the name of the C Compiler to use. On a Linux system, cc is almost always a link to GCC.

On some proprietary UNIX OperatingSystems, such as Solaris, the default cc is just a Shell script that prints out something to the effect that you have not paid for the additional software development component of the system.

Country Code
A unique two-letter abbreviation of a country name, such as NZ, AU, US, GB or DE. Used in DNS for ccTLDs, in locales, etc. ISO standard 3166 has a list of codes; on a Linux distribution you might find this in /usr/share/zoneinfo/

Credit Card
A small piece of plastic that lets you spend money you don't have.