Origin and history of plank

1540s, "plan of action, scheme, design;" 1550s, "ground-plan, drawing, sketch," senses now obsolete, from French plateforme, platte fourme, literally "flat form," from Old French plat "flat, level" (see plateau (n.)) + forme "form" (see form (n.)). These senses later went with plan (n.).

 The sense of "raised, level surface or place" in English is attested from 1550s, especially "raised frame or structure with a level surface." Specifically in geography, "flat, level piece of ground," by 1813. The railroad station sense of "raised walk along the track at a station for landing passengers and freight" is from 1832.

The U.S. political meaning, "statement of political principles and of the course to be adopted with regard to certain important questions of policy, issued by the representatives of a political party assembled in convention to nominate candidates for an election," is from 1803. It is probably originally an image of a literal platform on which politicians gather, stand, and make their appeals, and perhaps it was influenced by the earlier sense in England of "set of rules governing church doctrine" (1570s). In 19c., platform was used generally in a figurative sense for "the function of public speaking," and even was a verb, "to address the public as a speaker."

"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.