Jailbreaking is the process of removing software restrictions that Apple implements on your iDevice.
Jailbreaks are made through a series of Kernel patchs. This is done by finding Exploits in the software.
Having a Jailbroken Device allows users to have complete freedom over their iDevice by allowing users to install applications
that are non approved by Apple. Most Jailbreaks come bundled with a application known as Cydia.
Cydia allows users to search and install custom applications and firmware