The word nouveau riche (French for "new rich" or "new wealthy") in English is used in a pejorative manner to describe people who managed to accumulate a large sum of money and wealth within their own generation (such as by winning in lottery or through prosperous businesses, for example), unlike the vieux riche ("old money", "old rich"), whose net worth was acquired through inheritance and come from generations, and are often perceived to lack the refinement and etiquette traditionally attributed to the old rich by the latter.
Sociologically speaking, "nouveau riche" refers to a person who formerly had belonged to a lower social class and economic stratum within that class; and that the new money, which constitutes his/her wealth, granted them upward social mobility and provided the means for conspicuous consumption, the buying of goods and services that signal membership in the upper class.