The term "Piracy" is very common for the action of copying files, either for money or free of charge. One thing that should be noted about it is that the original pirates were sea-faring robbers, who took hold of ships, stole the goods, killed the people who were on board, and burned the ships. It would be a bit of a stretch to label a 10-years-old child who duplicated a CD of Music or several copyrighted files to his friend, after such villains.

I personally believe that the term "Piracy" in its applied context is quite harmless and is cognitively sound. However, I will not use the term here below.