X
on beer-casks indicates beer which paid ten shillings duty, and hence it came to mean beer of a given quality. Two or three crosses are mere trademarks, intended to convey the notion of twice or thrice as strong as that which pays ten shillings duty.
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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Entry taken from
Dictionary of Phrase and Fable,
edited by the Rev. E. Cobham Brewer, LL.D. and revised in 1895.