Switch

(swich)(n.)(1) Innetworks, a device thatfilters and forwardspackets between LAN segments. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of theOSI Reference Model and therefore support any packet protocol. LANs that use switches to joinsegments are calledswitched LANs or, in the case of Ethernet networks,switched Ethernet LANs.

(2) A small lever or button. The switches on the back ofprinters and onexpansion boards are calledDIP switches. A switch that has just two positions is called atoggle switch.

(3) Another word foroption orparameter — a symbol that you add to acommandto modify the command’s behavior.

See also Webopedia’s “Did You Know… Routers, Switches and Hubs: What’s the Difference?“