(1) A mechanical or electronic device that directs the flow of electrical or optical signals from one side to the other. Switches with more than two ports, such as a LAN switch or PBX, are able to route traffic.
With regard to a simple on/off switch, remember... Open is "off." Closed is "on."
(2) In programming, a bit or byte used to keep track of something. Sometimes refers to a branch in a program.
(3) A modifier of a command.
Mechanical and Semiconductor Switches The semiconductor switch (transistor) performs the same function as an on/off light switch on the wall. Instead of being manually closed, the switch is electronically closed by pulsing the semiconductor material, which makes it conduct.