The Nepalese caste system is the traditional system of social stratification of Nepal. The Nepalese caste system broadly borrows the classical Chaturvarnashram model consisting of four broad social classes or varna:Kshatriya, Vaishya,Brahmin and Sudra. The caste system defines social classes by a number of hierarchical endogamous groups often termed jaat. This custom was traditionally only prevalent in the Hindu societies of the Khas/Parbatiya, Madhesi , Newars. However, since the unification of Nepal in the 18th century, Nepal's various indigenous "Adivasi/Janajati" tribes have been incorporated within the caste hierarchy, to varying degrees of success. Despite of the forceful integration among the pan-Hindu social structure, the ethnic indigenous groups do not adhere to or fall under the caste system.
The social structure of caste-origin Hill Hindu or Khas groups is simple, reflecting only three groups in hierarchy, and there is no fourth varna within this category. The mother tongue of these groups is Nepali. In 2001 the CBS recorded only nine groups in the caste-origin Hill Hindu groups.
Before the king rule there were not caste origin of madhesi.They are origin at india.They are entered from india.Neighbouring country of Nepal.Before they were less in number but after a 10 years one by one they all entered in nepal and started a business and began to settle at Nepal.After a loktantra they got citizenship and began to take part in politics forcing by india..now they are called as madhesi but real madhesi was a Tharu
The social structure of the caste-origin Madhesi Hindu groups is complex, reflecting four varna groups with distinct hierarchical structure within them. These various cultural groups belong to four distinct language groups: Maithili, Bajika, Bhojpuri, Tharu and Awadhi. In 2001 the CBS recorded 43 caste-origin Hindu groups in the Madhesh.