DCP (Digital Cinema Package) is a digital film copy. It is used for screening in a cinema, whereby the image and sound data are available in a special data format.
The specifications for this were laid down by the DCI (Digital Cinema Initiatives), an association of major Hollywood studios in the “Digital Cinema System Specifications”.
The goal was to prevent a format war during the transition into the digital age to avoid high costs for film distributors & protect films against piracy.
Since the standard is open, no license fees are charged, and it offers high quality and security, it became the standard for digital cinema worldwide.
Read more about Digital Cinema System Specification here .