Latin, juncus, from jungo, to join: used for binding, making baskets, mats. The juncus maritimus is useful in binding together the loose sands of the sea-shore, and obstructing the incursions of the sea. The juncus conglomeratus is used in Holland for giving stability to river-banks and canals. (See Rush.)
Salt meat supplied to vessels for long voyages; so called because it is hard and tough as old rope-ends so called. Ropes are called junks because they were once made of bulrushes. Junk is often called salt horse.
(See Harness Cask.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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