noun
the highest social class in some countries : the people who have special titles (such as dukeand duchess ), who typically own land, and who traditionally have more money and power than the other people in a society
(source-Merriam-Webster)
I encounter this word in the reading “Anatomy of Fascism”. I found the word in the sentence ” There was a huge disparity between the riches of the aristocracy and the poverty of those working on the land or in the cities”. After I look it up in the dictionary, I know it means the highest social class in some countries.