To jailbreak means to modify a smartphone or tablet to remove the restrictions its manufacturer built in. When you buy an iPhone or iPad, Apple decides which apps you can install and what changes you can make to the system. A jailbroken device lets you bypass these rules, installing apps from anywhere and customizing features Apple normally locks down.

People might jailbreak devices to use apps not available in Apple's App Store, change how their home screen looks, or access system files normally hidden.

There are serious downsides, though. Jailbreaking usually voids your warranty, meaning the company won't help if something breaks. It can make your device less secure, since those manufacturer restrictions help protect against malicious software. Software updates might not work properly anymore. Many apps, especially banking apps, won't run on jailbroken devices because they're considered less secure.

The word also appears in other contexts. In artificial intelligence, researchers talk about jailbreaking AI systems when they find ways around the safety rules programmed into chatbots. Prison escapes are sometimes called jailbreaks too.