I've only ever heard "jailbroken" as using exploits to take control of a device that is intended by the vendor to be locked down - hence, breaking out of jail.

I've only ever heard "jailbroken" as using exploits to take control of a device that is intended by the vendor to be locked down - hence, breaking out of jail. I've only ever really heard of it being a term on iOS devices - on Android it's known as "rooting". Bootloader unlocked generally means that the vendor permits the execution of arbitrary operating system code, ie there is no jail to break out of.