What is it?
Creative Commons is a set of licenses which gives the user permission to do various things with the original content, such as reuse, revise, remix and redistribute it without needing to obtain written consent from the creator. View the license key, here.
Am I giving away my copyright using a CC license?
NO. In fact, you are retaining your copyright as the creator of the content! Depending which license you apply to your work, you are simply announcing to the world that you are okay if people use your creative work to create something new, as long as they give you credit (the "BY" in CC-BY) and abide by the license guidelines. It's important to read the list of considerations before choosing a license for your work.