This would be on the back cover of a DVD, resembling which region it is
There are 8 dvd regions given to scertain countrys, for example England is one of many countries belonging to region 2. The region code is so that film distributors can control aspects of release, for example; content, price and release date. The code means dvds from a different region to your dvd player won't work, but there are dvd players that can play multi region dvds and laptops can play dvds from different regions (but they may need to have software installed).