A button may refer to any of the following:
1. When referring to hardware, a button is a physical switch that controls a function of a device. The picture is an example of the power button found on the front of a computer.
What does the power button do?
- If the computer is off and the power button is pressed, the computer turns on.
- If the computer is sleeping and the light is flashing, the power button will wake up the computer.
- With more modern computers, if the computer is on and running, pressing and letting go of the power button will either put the computer into sleep mode or it will turn off the computer with a proper shutdown process.
- With newer computers, if the computer is on and running, pressing and holding the power button for three to five seconds will turn the computer off without shutting down properly.
What is the power button symbol?
The de facto standard for the power button symbol is an almost complete circle with a vertical line going from above the circle down to the center of the circle as shown on this page. The symbol represents a "0" (zero) and a "1" (one), which is the characters used in the computer's binary language and also represents off (0) and on (1).
2. When referring to software, a button is used to perform a certain function. For example, the Windows Start button is used to open the Start Menu. See the push-button dictionary definition for further information and an example.