a background process that runs whenever Windows is running

a good choice when an application needs to run unattended, regardless of whether users are logged on or not

a highly specialized type of application designed to run for extended periods in its own Windows session, usually with no user interface

a long-running application without a user interface or any visual output

an 'always on' application that is constantly running in the background of your system

an application that does not have a user interface

an application that requires no user interface and can be automatically started at system startup

an application that sits in the background, waiting for you to call it or for some system event to happen

an application which does not have a user interface and runs without human intervention

a process that runs unattended and doesn't have a user interface

a specially designed application that can be started automatically at system boot

A Windows service is an application that starts when Windows is booted and runs in the background as long as Windows is running. It is very similar in concept to a Unix daemon.