Jailbreaking refers to the process of removing all restrictions imposed on an iOS device. iOS devices that are vulnerable to being jailbroken include but are not limited to; Apple iPad, Apple iPod Touch, Apple TV 2 and all Apple iPhone smartphones.
Jailbreaking allow root access to system files that can be manipulated to enable installation of apps, themes, and extensions that are not supported by Apple , or unavailable for download on Apple App Store.