A device that connects to your TV and some external source of signal, and turns what's in that signal into content on your screen. If you're lucky, it even does things when you press buttons on your RemoteControl box.

The signal source might be a satellite dish, a cable (as in, cable TV), a phone line, a DSL connection or maybe even an ordinary UHF/VHF antenna. And that's just for starters.

Content, in this context, could mean any or all of video, audio, internet pages, interactive games, or a dozen other possibilities.

-- JonGreen (who's a software developer in the SetTopBox industry)