When you get the scene of Android custom ROMs, rooting, and hacking, it can be hard to understand Android terminology. We remember just getting started and staring blankly at a page of terms we couldn’t recognize. People experienced with this kind of thing tend to throw around terms like kernel and firmware like everyone else has a background as a system admin or has contributed to open source projects before.

We’ll try to help you out here with a short cheat sheet of Android Terminology that you’re likely to encounter while trying to hack or root your Android phone. This list is not comprehensive, but it should help you get started. With any luck, you won’t be as confused as we were when starting out. Here are just a few of the terms that you’ll need to know if you want to make any kind of serious modifications.

Understanding the Android Vocabulary

1. Rooting

This is one of the most important functions you can do on an Android phone. Rooting is the critical first step that allows you to do everything else. Without root, there is no way to install a custom recovery, ROM, or kernel.


The term is a holdover from Linux. Root access is when the user gains permission to access every part of the Android system, making you a superuser. Most devices run in sandboxed mode to prevent inexperienced users from inadvertently damaging something.

However, advanced users want root access because it lets them change critical system files. If you can’t change those files, then you can’t do any of the really cool hacks. Having root access is always helpful.

2. Linux

Linux is a free and open-source operating system. One of its core components is the Linux kernel, a bit of software that helps run the system. The Linux kernel is the basis of Android. This becomes important because many things you see on Linux (such as kernels and root access) are available on Android.


3. Kernel

A kernel is a piece of software that acts as an interface between the phone’s hardware and software. Most Android enthusiasts try different kernels in order to change how it handles power management. With apps like SetCPU, you can change how much battery your phone uses.

4. Under-and overclocking

This is a holdover term from PC chips. A clock speed measures how fast your phone’s processor runs, essentially. By adjusting the kernel’s settings, you can change the phone’s clock speed.


Lowering the speed can save a lot of battery, but it makes your phone run slowly and with some lag. Overclocking is helpful for squeezing extra performance out of a device but comes at the cost of battery life.

5. ROM

Read-Only Memory (ROM) is a file that contains the files needed to set up the Android system. A ROM is like an entire Android system contained into one compressed .zip file.

Every Android phone comes with a preinstalled ROM, often called the stock ROM. This is the basic version of the phone’s operating system. It’s what gets updated by the manufacturer when a new version of Android releases.


Some (read: most) Android modders like to install a custom ROM. Because Android is open-source, the community can make its own ROMs with special features that you won’t find on stock ROMs.

Building a custom ROM is a lengthy and difficult process. It has to be custom-tailored for each individual phone. The long development process means that good custom ROMs take a time to make.

However, we prefer custom ROMs for a few reasons. First, they usually include extra customization and flexibility that stock ROMs don’t offer. Second, custom ROMs often offer new versions of Android before stock ROMs do.

6. Flashing

A general term for installing something on your phone. Most often used with ROMs or other system-level modifications.

7. Recovery

A special mode for installing custom ROMs and other hacks. Most modders replace their stock recovery with a custom, community-built one for the added features. For more, see our guide to recovery mode.


8. Bootloader

A small piece of software that starts up the Android system when you turn on a phone. It can also boot the device into recovery. Phone manufacturers sometimes lock this to prevent unauthorized modifications, a practice which we abhor.

9. Nandroid

A backup of your entire system which you can save from recovery mode. We usually save a Nandroid backup before attempting any serious hacking as it’s a great failsafe.

Final Thoughts

When you’re just starting down the path of taking apart your Android device to make it better, things can seem confusing. With this guide, you can understand the Android terminology and with some focus, you can root your phone.

(Article updated on 27th February 2020)