What does "chaldron" mean?

Chaldron: An English dry measure, being, at London, 36 bushels heaped up, or its equivalent weight, and more than twice as much at Newcastle. Now used exlusively for coal and coke. Note: In the United States the chaldron is ordinarily 2,940 lbs, but at New York it is 2,500 lbs. De Colange.

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