switchyoudaoicibaDictYouDict[switch 词源字典]
switch: [16] Switch originally denoted a ‘thin flexible twig’; it may have been borrowed from Middle Dutch swijch ‘bough, twig’. From the noun was derived the verb switch. This originally meant ‘beat with a switch’, but in the early 19th century the sense ‘bend or waggle to and fro like a flexible stick’ emerged, and this led on in the middle of the century via ‘divert’ to ‘turn off a train on to another track’ (the usage developed in American English, where the apparatus used for this is still known as a switch, as opposed to British English points).

By the end of the century this had broadened out to ‘connect or disconnect by pushing a contact to or fro’. The notion of ‘exchanging’ or ‘swopping’ did not emerge until as recently as the 1890s.
[switch etymology, switch origin, 英语词源]
switch (n.)youdaoicibaDictYouDict
1590s, "slender riding whip," probably from a Flemish or Low German word akin to Middle Dutch swijch "bough, twig," or swutsche, variant of Low German zwukse "long thin stick, switch," from Germanic base *swih- (cognates: Old High German zwec "wooden peg," German Zweck "aim, design," originally "peg as a target," Zwick "wooden peg"), perhaps connected with PIE root *swei- (2) "to swing, bend, to turn."

The meaning "device for changing the direction of something or making or breaking a connection" is first recorded 1797. "The peg sense suits the mech(anical) applications" [Weekley], cognates: switchblade, and these senses in English may be a direct borrowing from those senses in Continental Germanic languages rather than a continuation of the "pliant wand" sense. The meaning "a change from one to another, a reversal, an exchange, a substitution" is first recorded 1920; extended form switcheroo is by 1933.
switch (v.)youdaoicibaDictYouDict
1610s, "to strike with a switch," from switch (n.). Related: Switched; switching. The meaning "turn (off or on) with a switch device" is first recorded 1853 of trains on tracks, 1881 of electricity, 1932 of radio or (later) television. Sense of "shift, divert" is from 1860. Meaning "to change one thing for another" is recorded from 1919. Switch-hitter is 1945 in baseball slang; 1956 in the sense of "bisexual person."