Whiskey is a vast spirit category that encompasses many different types, including bourbon. However, all whiskies are distilled from grains and aged in oak barrels.
Bourbon is distilled from a combination of grain, yeast, and water. "Mash bill" is the mix of grains used in making whiskey; for bourbon, the mash bill must have at least 51% corn.
Most bourbons on the market contain 60 to 86% corn; other grains used in the mash bill are rye, wheat, and barley. No artificial flavors or colors are used in the bourbon industry.
Bourbons must be aged in charred new oak barrels and for it to be labeled a "straight," it has to be aged for at least two years. Most bourbons are in the 40 to 50% ABV range.