Root, at least the way we’re talking about it here, is the superuser. Your Android phone uses Linux permissions and file-system ownership. You are a user when you sign in, and you are allowed to do certain things based on your user permissions. Apps you install are also given a type of user ID, and they all have permissions to do certain things — you see those when you install them on older versions of Android, or you are prompted to allow them on Marshmallow or higher — in certain folders with certain files. Root is also a user. The difference is the root user (superuser) has permissions to do anything to any file anywhere in the system. This includes things we want to do, like uninstall application forced on us, or things we don’t want to do that can put your Android in an unusable state. When you’re doing things with superuser permissions, you have the power to do anything.