Cathay is the Anglicized version of "Catai" and an alternative name for China in English. "Catai" was originally the name given to northern China by Marco Polo (he referred to southern China as Manji). "Catai" itself derives from the word Khitan (契丹 Qìdān), the Chinese name of a tribe ruling predominantly in northern China during Polo's visits. Travels in the Land of Kubilai Khan by Marco Polo has a story called: 'The Road to Cathay.' In the English language, the word Cathay was widely used for China until the 19th century when it was replaced by "China". The term may still be used poetically or in certain proper nouns, such as Cathay Pacific Airways or Cathay Hotel. A person from Cathay (i.e., a Chinese) was also written in English as a Cathayan.
Below is the etymological progression from Khitan to Cathay as the word travelled westward: