set-top box
From Longman Dictionary of Contemporary Englishset-top boxˈset-top ˌbox noun [countable] British English a piece of electronic equipment that is connected to your television to make it able to receive a different form of broadcasting, especially digital signalsFrom Longman Business Dictionaryset-top boxˈset-top ˌbox noun [countable] a piece of equipment that allows you to use the Internet on your television, and to receive digital television