You can think of Windows in the PC market as a UI, providing you with a very user friendly environment, in the early days you would run a PC through DOS no graphics. Certain manufactures like to put a different UI or skin as Jay puts it on top of the standard Android interface. A launcher on the other hand is a short cut which will launch a program, sometimes it provides a quick link to a web window, other times it is a shortcut (normally with an icon to start an App). Of course I could be totally wrong as these days definitions change.
Love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful, and optimistic. And we will change the world. - Jack Layton (1950-2011)
Blackberry PlayBook 64GB Nokia 1020, Microsoft Surface PRO 2