KIT KAT bars are a popular chocolate-covered wafer snack produced by Nestle. The name is derived from the phrase 'KIT Kat', which is a term used to describe a person who is cheerful and friendly. The bar was first introduced in the United Kingdom in 1935 and has since become a global phenomenon. It is now available in over 100 countries and is one of the most recognizable chocolate brands in the world.