What defines media?

Due to the excessive talk about ITV programmes such as 'Im a Celebrity Get Me Out OF Here', where they find "celebrities" and stick them in the jungle for 3 weeks, and 'Xfactor', where Simon Cowell thinks he owns the world, it made me think about what is and isnt media! Surely media is everywhere. For example, taking a trip in the car, the radio is media. MEDIA IS EVERYWHERE! So how do you know what counts as media, where is the line that lets you know what media is, and what is the opposite of Media? these questions need to be answered...Mr. VS over to you.