/ kɑːsk; NAmE kæsk/ noun
a small wooden barrel used for storing liquids, especially alcoholic drinks; the amount contained in a cask :
a wine cask / a cask of wine
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WORD ORIGIN
early 16th cent.: from French casque or Spanish casco helmet. The current senses appear only in English; from the late 16th to the late 18th centuries the word also denoted a helmet.