To remove a program, an app, or a driver from a computer or phone properly — not just deleting the icon, but taking out the files and settings that were put in when it was installed. The opposite of *install*.

It is a normal, everyday computing word, used by ordinary users and technicians alike: "Try uninstalling it and installing it again" is the oldest advice in tech support. In practice people also use it loosely for phones, where you would more often say *delete* or *remove the app* — nobody will blink at "I uninstalled Instagram".

It can also be a noun in technical writing ("a clean uninstall", "the uninstall failed"), and *uninstaller* is the little program that does the job. Note that it applies only to software: you cannot uninstall a shelf or a machine — for physical things, people say *remove* or *take out*. The word is young, born with personal computers in the 1980s-90s, which is why it sounds plain and mechanical rather than literary.