An archaic or obsolete term, possibly referring to a unit or a specific object whose exact meaning is lost to history.
The etymology is uncertain; this appears to be an extremely rare or obsolete word with unclear origins, possibly from Middle English or Welsh influences.
Cyul is one of those wonderful 'ghost words' that lexicographers find in old manuscripts—it appears in historical records but its meaning is so forgotten that even experts can only guess at what it originally meant.
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