What does the symbol 'CC' signify?

The CC symbol signifies Creative Commons, a set of public copyright licences for sharing creative work.

It does not simply mark copyrighted material, which uses the copyright symbol.

There is no standard mark called copyable material tied to CC.

Copying Commons is not a real licensing scheme.

Creative Commons licences let creators grant reuse rights while keeping some rights.

A common example is CC BY, which requires attribution to the author.