Any physical object which makes an electrical connection when depressed, allowing the performing of some function, such as turning on a device or ringing a doorbell. Such a device is also found on a computer mouse.
In computing, a button is an analogous feature on a computer display, comprising a graphical object or icon found often in dialog boxes or as parts of menus in multimedia presentations. When clicked using the mouse or other means (such as a touchscreen or often by hitting the Return key), the button activates some feature or function. Such a button is often known as a light button.