What ia a switch?

switch |swi ch |

noun

1 a device for making and breaking the connection in an electric circuit : the guard hit a switch and the gate swung open.

• Computing a program variable that activates or deactivates a certain function of a program.

2 an act of adopting one policy or way of life, or choosing one type of item, in place of another; a change, esp. a radical one : his friends were surprised at his switch from newspaper owner to farmer.

3 a slender flexible shoot cut from a tree.

4 a junction of two railroad tracks, with a pair of linked tapering rails that can be moved laterally to allow a train to pass from one line to the other.

5 a tress of false or detached hair tied at one end, used in hairdressing to supplement natural hair.

verb [ trans. ]

1 change the position, direction, or focus of : the company switched the boats to other routes.

• adopt (something different) in place of something else; change : she's managed to switch careers.

• [ intrans. ] adopt a new policy, position, way of life, etc. : she worked as a librarian and then switched to journalism.

• substitute (two items) for each other; exchange : after ten minutes, listener and speaker switch roles.

2 archaic beat or flick with or as if with a switch.

PHRASAL VERBS

switch something off turn off an electrical device. • ( switch off) informal cease to pay attention : as he waffles on, I switch off.

switch something on turn on an electrical device.

DERIVATIVES

switchable |ˈswɪtʃəbəl| adjective

ORIGIN late 16th cent. (denoting a thin tapering riding whip): probably from Low German.