A plug or stopper, particularly one used to seal or close an opening in a cask, barrel, or similar container.
From French bondon, possibly from Old French bon (good) + don (gift), or from a Celtic root. The term has been used in English since at least the 16th century for barrel closures.
A bondon is what keeps centuries-old wine safe—coopers (barrel makers) depended on perfectly-fitted bondons, and a winemaker's reputation hinged on this tiny piece of wood doing its job.
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