E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A coop for wine bottles. The bottles lie in a slanting position in the coop, and may be transported in it from place to place. We find allusions to six-bottle coopers not unfrequently, i.e. coops or cases containing six bottles. Compare hen-coops, cooped up, etc. (Latin, cupa, a cask; our cup.)