Word familynounsetnesssettersettingsetbacksetlineset piecesetscrewset squareset-top boxverbset
ˈset-top ˌbox noun [countableC]British EnglishBrE
a piece of electronic equipment that is connected to your television to make it able to receive a different form of broadcasting, especially digital signals 数码信号接收器，电视机顶盒〔连接在电视机上的一种接收数码信号的电子设备〕
From Longman Business Dictionary
set-top boxˈset-top ˌbox noun [countableC]
a piece of equipment that allows you to use the Internet on your television, and to receive digital television