ADB: Android Debug Bridge. A tool used to connect and send commands to your Android phone from a desktop or laptop computer.
AOSP: The Android Open Source Project. When you hear about Android being “open source,” this is what we’re talking about. It’s a repository of the code released by Google, which can be downloaded and compiled by anyone. (If you know how.)
APK: Android application package file. Each Android application is compiled and packaged in a single file that includes all of the application’s code (.dex files), resources, assets, and manifest file. The application package file can have any name but must use the .apk extension. For example: myExampleAppname.apk. For convenience, an application package file is often referred to as an “.apk”.
Bloat(ware): Applications — usually unwanted — that are preloaded onto a device. It’s a bit subjective as to what constitutes bloatware, and the flip side is that these applications are what allow carriers to sell phones and tablets at subsidized prices.
Bootloader: An internal mode on a phone that helps in the flashing of ROMs and other behind-the scenes actions.
Cyanogen: The online handle of one Steve Kondik, relatively famous in the hacking and modding community and the creator of the CyanogenMod series of ROMs.
Fastboot: Another mode akin to the bootloader, from which you can manually flash low-level components onto a phone.
Flashing: The ROM memory used in smartphones and tablets etc. is often same as flash memory found in SD cards and USB flash drives, simply optimized for better speed and performance while running the operating system.
Hard Reset: The act of resetting your phone to its “factory” state. Erases all user data, logins and passwords. May or may not erase what’s on the internal storage or microSD card, too.
IMEI Number: Stands for International Mobile Equipment Identity. Basically a unique identification number assigned to every phone.
Kernel: A kernel is a layer of code that allows the OS and applications to interface with your phone’s hardware. The degree in which you can access your phone’s hardware features depends on the quality of code in the kernel. The homebrew (rooting) community for HTC has made several kernel code improvements that give us additional features from our hardware that the stock kernel does not. When you flash a custom ROM, you automatically get a kernel. But you can also flash a standalone kernel ROM on top of the existing one, effectively overwriting it. These days, the difference in custom kernels is less about new features and more about alternate configurations. Choosing a custom kernel is basically choosing one that works best with your ROM.
Overclock: To increase the speed of your CPU.
ROM: Literally, “Read Only Memory.” In Android, it’s what you load for a major software update. “Custom ROMs” are just that — developed outside control of a manufacturer or carrier.
Recovery Mode: A small separate operating mode you can boot your device into, used for device administration. Two popular custom recovery modes are Amon Ra and Clockwork.
Rooting: A process allowing users of mobile phones, tablet PCs, and other devices running the Android operating system to attain privileged control (known as “root access”) within Android’s subsystem. Rooting is often performed with the goal of overcoming limitations that carriers and hardware manufacturers put on some devices, resulting in the ability to alter or replace system applications and settings, run specialized apps that require administrator-level permissions, or perform other operations that are otherwise inaccessible to a normal Android user. Rooting is analogous to jailbreaking devices running the Apple iOS operating system or the Sony PlayStation 3. On Android, rooting can also facilitate the complete removal and replacement of the device’s operating system.
Tethering: The act of using your smartphone’s data to provide Internet access to another device, such as a laptop. Can be done wirelessly, or via a USB cable.