A technological measure to prevent you, the consumer, from enjoying content that you paid for because it's from another country. Virtually all DVD players have this built in, as well as video game consoles. In the USA , it is illegal to modify a device in such a way as to defeat the region lock. This evil invention allows hated countries (that is countries with a race that is not preferred) to get movies and games last while Aryan countries get them first, and it makes the authentic legitimate original less valuable because of the restrictions put on it.
The fact that there is a region lock on my game console reinforces my stereotype that the U.S.A. is nowhere near a free country.