Whisky, or Whiskey, refers to a broad category of alcoholic beverages that are distilled from fermented grain mash and aged in wooden casks (generally oak).

Different grains are used for different varieties, including: barley, malted barley, rye, malted rye, wheat, and maize (corn). Whisky derives from the Gaelic word for "water" (uisce or uisge), and is called in full uisge-beatha (in Scotland) or uisce beatha (Ireland), meaning "Water of Life". It is related to the Latin aqua vitae, also meaning "water of life". It is always Scotch whisky, and Irish whiskey; other countries may use either spelling.

The first written record of whisky comes from 1405 in Ireland, where it was distilled by monks. It is also mentioned in Scotland in 1496. However it is thought that whisky had already been around for at least several hundred years prior. When or where whisky was first distilled is unknown and the local, undocumented beverage production during the period makes identification of the drink's origin difficult. Additionally, it is possible that different groups discovered processes of distillation completely independently of one another.

Some scholars believe distilled spirits were first produced between the 8th century AD and 9th century AD in the Middle East with the art of distillation being brought to Ireland and Britain by Christian monks. A popular legend is that St. Patrick introduced distillation to Ireland and Britain, however it is likely he lived around the 5th century AD. It is also possible that the distillation process was discovered in Ireland and possibly Britain (either independently or in precursor to Arabian distillation) by farmers as a way of making use of excess grain after harvest.

more info on: http://en.wikipedia.org/wiki/Whiskey