The Collaborative International Dictionary
Jamaica \Ja*mai"ca\, n. One of the West Indian islands.
Jamaica ginger, a variety of ginger, called also white ginger, prepared in Jamaica from the best roots, which are deprived of their epidermis and dried separately.
Jamaica pepper, allspice.
Jamaica rose (Bot.), a West Indian melastomaceous shrub ( Blakea trinervis), with showy pink flowers.
Wikipedia
Jamaica Ginger extract, known in the United States by the slang name "Jake," was a late 19th-century patent medicine that provided a convenient way to bypass Prohibition laws, since it contained between 70-80% ethanol by weight.
Usage examples of "jamaica ginger".
He found a box of liver pills, a bottle of Jamaica ginger, and some iodine--not an encouraging array for a man fifteen miles of untrodden snow from the nearest human habitation.