An archaic or dialectal term, possibly relating to a type of stone, building material, or geological formation (exact meaning uncertain in modern usage).
Possibly from Old French or dialectal sources; etymology is obscure. The word may be related to 'chaux' (lime/limestone) but this connection is unclear.
This word is so archaic that etymologists disagree on its meaning—it's exactly the type of lost vocabulary that shows how much English has changed since medieval times, with entire categories of things having disappeared from common speech.
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