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 pressing and letting go of the power button either puts the computer into sleep mode or turns off the computer with a proper shutdown process.
- With newer computers, if the computer is on, pressing and holding the power button for three to five seconds turns the computer off without shutting down properly.
What is the power button symbol?
The standard symbol for the power button is the "standby symbol," as defined by the IEC. The symbol combines a vertical line and a circle, representing "on" and "off," respectively. It's defined in IEC 60417, Graphical Symbols for Use on Equipment. The symbol also resembles a "1" and "0," the binary numbers representing "on" and "off."
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.