Daemon (computer software)
From Citizendium, the Citizens' Compendium
A daemon is a computer program that runs by itself, as opposed to being directly controlled by a user. Typically, there are dozens of these daemons started at bootup, and doing everything from running scheduled tasks to monitoring hardware activity, such as connection requests received by a network adapter. Daemon is a fanciful term used most commonly in operating systems derived from Unix. In Windows, daemons are simply called "services".
[WP]

