A radio button is a round circle representing choices in a common option list form in a graphical user interface. Below is an example of what the radio button looks like in your browser.
Tip: Radio buttons are typically used when only one option should be used.
What is the difference between a check box and a radio button?
A check box is always a square box and allows for one or more items to be selected. A radio button is typically a circle and only allows for one item to be selected.