also switch-board, "device for making interchangeable connections between many circuits," 1867, from switch (n.) + board (n.1).
Entries linking to switchboard
switch n.
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 *swih- (source also of 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]; also compare switchblade. These senses in English might 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.
board n.1
"piece of timber sawn flat and thin, longer than it is wide, wider than it is thick, narrower than a plank;" Old English bord "a plank, flat surface," from Proto-Germanic *burdam (source also of Old Norse borð "plank," Dutch bord "board," Gothic fotu-baurd "foot-stool," German Brett "plank"), perhaps from a PIE verb meaning "to cut." See also board (n.2), with which this is so confused as practically to form one word (if indeed they were not the same word all along).
In late Old English or early Middle English the sense was extended to include "table;" hence the transferred meaning "food" (early 14c.), as "that which is served upon a table," especially "daily meals provided at a place of lodging" (late 14c.). Compare boarder, boarding, and Old Norse borð, which also had a secondary sense of "table" and an extended sense "maintenance at table." Hence also above board "honest, open" (1610s; compare modern under the table "dishonest").
A further extension was to "table where council is held" (1570s), from whence the word was transferred to "leadership council, persons having the management of some public or private concern" (1610s), as in board of directors (1712).
"Bow to the board," said Bumble. Oliver brushed away two or three tears that were lingering in his eyes; and seeing no board but the table, fortunately bowed to that.
The meaning "table upon which public notices are written" is from mid-14c. The meaning "table upon which a game is played" is from late 14c. The sense of "thick, stiff paper" is from 1530s. Boards "stage of a theater" is from 1768.