Etymology
Advertisement
whip-saw (n.)
also whipsaw, 1530s, from whip + saw (n.). As a verb from 1842. Related: Whip-sawed; whip-sawing.
Related entries & more 
Advertisement
saw (v.)

"cut or cut in pieces with a saw," c. 1200, sauen, saghen, from saw (n.1). Strong conjugation (sawn) began by c. 1400 on model of draw, etc. Related: Sawed; sawing. Sawed-off "short, cut short" is attested by 1887, by 1898 specifically of shotguns.

Related entries & more 
see-saw (v.)
also seesaw, "move up and down," 1712, from see-saw (n.). Related: See-sawed; see-sawing.
Related entries & more 
pit-saw (n.)

"large saw used for cutting timber, operated by two men, one (the pit-sawyer) standing in the pit below the log that is being sawed, the other (the top-sawyer) standing on the log," 1670s, from pit (n.) + saw (n.1).

Related entries & more 
prism (n.)

1560s, in geometry, "a solid whose bases or ends are any similar, equal, and parallel plane polygons, and whose sides are parallelograms" (not always triangular), from Late Latin prisma, from Greek prisma "a geometrical prism, trilateral column," (Euclid), literally "something sawed (as a block of wood), sawdust," from prizein, priein "to saw" (related to prion "a saw"), which is of uncertain origin. Euclid chose the word, apparently, on the image of a column with the sides sawn off.

Specific sense in optics, "an instrument (usually triangular) with well-polished sides of glass, quartz, etc., which refracts light and spreads it in a spectrum," is attested from 1610s.

Related entries & more 
Advertisement
rail (n.1)

"horizontal bar passing from one post or support to another," c. 1300, from Old French raille, reille "bolt, bar," from Vulgar Latin *regla, from Latin regula "rule, straight piece of wood," diminutive form related to regere "to straighten, guide" (from PIE root *reg- "move in a straight line").

 In U.S. use, "A piece of timber, cleft, hewed, or sawed, inserted in upright posts for fencing" [Webster, 1830]. Used figuratively for thinness from 1872. By 1830s as "iron or steel bar or beam used on a railroad to support and guide the wheels." To be off the rails "out of the normal or proper condition" in a figurative sense is from 1848, an image from railroads.

Related entries & more 
plank (n.)

late 13c. (c. 1200 as a surname), "thick board used in construction," from Old North French planke, a variant of Old French planche "plank, slab, little wooden bridge" (12c.), from Late Latin planca "broad slab, board," probably from Latin plancus "flat, flat-footed," from a nasalized variant of PIE root *plak- (1) "to be flat." Planche itself was also used in Middle English.

Technically, timber sawed to measure 2 to 6 inches thick, 9 inches or more wide, and 8 feet or more long. The political sense of "article or paragraph formulating a distinct principle in a party platform" is U.S. coinage from 1848, based on the double sense of platform. To be made to walk the plank, "be forced to walk along a plank laid across the bulwarks of a ship until one reaches the end and falls into the sea," popularly supposed to have been a pirate form of execution, is attested from 1789, and most early references are to slave-ships disposing of excess human cargo in crossing the ocean.

Related entries & more