Radio button

A radio button (or option button) is a type of graphical user interface element that allows the user to choose only one of a predefined set of options. They were named after the physical buttons used on older car radios to select preset stations &mdash; when one of the buttons was pressed, other buttons would pop out, leaving the pressed button the only button in the "pushed in" position.

Radio buttons are arranged in groups of two or more and displayed on screen as, for example, a list of circular holes that can contain white space (for unselected) or a dot (for selected). Adjacent to each radio button is normally shown a caption describing the choice that this radio button represents. When the user selects a radio button, any previously selected radio button in the same group becomes deselected. Selecting a radio button is done by clicking the mouse on the button, or the caption, or by using a keyboard shortcut.