What is the other on my iPhone 5?

I just synced my iPhone 5 and it says "other" is taking up 5.5 gb. What could this be from? I have no clue what is taking up so much room.

Some is the iOS software rest is like app save files, Catch files etc but it should t be taking up that much usually by even 1gb restore you iPhone and see if it helps

Can be many things: http://www.justtext.com/messageboards/20130215171154.html