Short answers, pulled from the story.
The Latin word nobilis first appeared as an informal designation for the political governing class. This term described families who had allied interests, including both patricians and plebeian families with an ancestor who had risen to the consulship through his own merit.
In medieval Europe, nobles held land or office under vassalage in exchange for allegiance and various military services to a suzerain. A fief often included fields, pasture, orchards, timberland, hunting grounds, streams, and infrastructure such as castles, wells, and mills.
Ethiopian nobility resembled its European counterparts until 1855 when Tewodros II ended the Zemene Mesafint period. Ethiopian nobility divided into two categories: Mesafint as hereditary nobility forming the upper echelon, and Mekwanin as appointed nobles often of humble birth.
The Twenty-Sixth Amendment of the Constitution of India passed in 1971 abolished all noble privileges within the Republic of India. China's bestowal of titles was abolished upon establishment of the People's Republic of China in 1949, and Brazil discontinued its nobility with proclamation of the First Brazilian Republic in 1889.
In the United Kingdom royal letters patent are necessary to obtain a title of the peerage. In 1999 all hereditary peers lost entitlement to sit and vote in the House of Lords leaving only 92 representatives elected by the peerage.