n.
     - a device for making and breaking an electrical connection. ▸Computing  a program variable which activates or deactivates a function. ▸Computing  a device which forwards data packets to an appropriate part of the network. 
- a change, especially a radical one.
- a slender, flexible shoot cut from a tree.
- N. Amer. a set of points on a railway track.
- a tress of hair used in hairdressing to supplement a person's natural hair.
v.
   - change in position, direction, or focus. ▸exchange. 
- 
(switch something off/on)
 turn an electrical device off (or on). ▸
(switch off)
 informal cease to pay attention. 
- archaic beat with or as if with a switch.
Derivative
  
  Etymology
  C16 (denoting a thin tapering riding whip): prob. from Low Ger.