"Oui" is a French word that means "yes" in English. Historically, this word and its cognate "oïl " meant "yes" in the northern areas of France.
In the southern parts of the country, people used the word "oc" to mean yes. This division is the traditional way of describing France's two major language groups, the langues d'oïl and the langue d'oc, or Occitan language. Because northern France eventually became more powerful politically, its tongue asserted itself as the standard French language, which has caused Occitan to die out. Although native speakers still exist, most dictionaries of French ignore Occitan usages, opting instead for the standard French terms.