mid-15c., "two-wheeled cart for hauling dung, stones, etc.," earlier an instrument of punishment of uncertain type (early 13c.), from Old French tomberel "dump cart" (Modern French tombereau), from tomber "(let) fall or tumble," possibly from a Germanic source (compare Old Norse tumba "to tumble," Old High German tumon "to turn, reel;" see tumble, v.). Notoriously the name given to the carts used to take victims to the guillotine during the Reign of Terror (though illustrations often show four-wheeled carts, not true tumbrels).