a two-wheeled cart or wagon typically designed to be hauled by a single horse or ox. Their original use was for agricultural work; in particular they were associated with carrying manure. Their most notable use was taking prisoners to the guillotine during the French Revolution.
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There were such few spectacles these days, other than the monotonous processions of tumbrils with their load of aristocrats for the guillotine!
Baroness Emmuska Orczy. The League of the Scarlet Pimpernel (1919)
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the king had given strict orders, that if at any time another appeared, it should be taken ashore, and with all its crew and passengers brought in a tumbril to Lorbrulgrud.
Jonathan Swift. Gulliver's Travels Into Several Remote Regions of the World (1726)