Bourbon is a type of American whisky (whiskey) made from maize, rye (rarely wheat) and malted barley, aged for at least two years in charred American oak casks. As a general rule, you should know that any bourbon is a whisky, but not any whisky is a bourbon. The malt used must be made from 51% maize, yeast, and water. It must be distilled at no more than 80% alcohol by volume, can only be produced in the USA and must be aged for at least two years. The origin of its name is somewhat uncertain, but it is assumed to have a connection to the French Bourbon dynasty, the state of Kentucky.
After the bourbon has been extracted, the casks are then used to age and ennoble other beverages such as wine, beer, or rum, thus lending them special, distinct notes.