The best definition of Zune should be the iTunes of Microsoft. This brand was first set up in 2006, and now it has been discontinued in 2011, Xbox as its substitute.
When it comes to Zune, we refer to at least 5 things and because of that, it's hard to define which one is exactly talking about. These 5 things are Zune player, Zune app, Zune Marketplace, Xbox Music pass, and Zune software. Then what do they mean? Learn more in the following passage.
It is a portable device for playing music and videos, also simply called "MP3 Player". It's small and for entertainment. You can use it just like iPod but not as Windows Phones.
It's an application, or the music player for Windows Phone. Again you can play music and videos with this app.
This is the same thing just like iTunes store. Within this Zune marketplace, you can get music, videos, podcasts, apps, games, and more. You can access this online store on various devices, including Zune Players, PCs, and Windows Phone 7. In this marketplace, some stuff are for free, and some are costing money. By the way, some countries/regions are not available with Zune Marketplace.
This Music Pass is a music subscription service available through Zune Marletplace. For example, if you pay a monthly fee, and you can download and stream songs without limitation to your PC, phone, and Zune player. Also, it's the same as Zune Marketplace that some countries and regions are not available with this service.
Zune app is the media player for Windows phones, and Zune software is for your computer. Besides, Zune software supports sync between your phone and PC.