Jailbreak: is the term used for the process of removing the limitations on iOS devices (iPhone, iPod Touch, iPad, Apple TV), and the user has full access to the operating system and can install applications outside the App Store. The jailbreak method is generally used for installing pirated applications or third party applications (third party) that usually cannot be found in the "App Store". When doing Jailbreak an iOS device to your phone and liberate possibilities are endless functions.
Root: Root of an Android is equivalent to Jailbreak iOS, except it's not illegal nor will cause major problems if not invent too. This of rooting is not very common among novice users as Android allows you to install applications even if they are not purchased in the "Play Store”. The name derives from the root which means "root", because when you root your phone, you have access to the root of the phone, and then you can do unimaginable changes to your android device.
Unlock: In both cases, it is a process that takes place in the cell to use it on any phone company and not necessarily where it was purchased. In English it is "Unlock". Remember there are different methods to make this process as there are GSM and CDMA networks, go here and pick out all the difference.
All these methods most often are fortunately grates. Do not fall for scams.