Pernod is the brand name of a type of liqueur called a pastis. Its relative in Greece is ouzo and in Spain ojen. Another French brand is Ricard. The leading characteristic of these drinks is their licorice flavour, which is produced either with licorice or anise. Its other interesting feature is that it clouds up with the addition of water.
Pernod is actually a successor of absinthe, the potent liquor that contained a toxic oil from wormwood in quantities that were thought to cause brain damage - and which was outlawed in 1915 in France. One of absinthe's leading manufacturers, Henri Pernod, then focused its efforts on the lower-alcohol, wormwoodless, anise-flavoured Pernod. Watch this video to learn the variety of uses for the popular liqueur aperitif Pernod.