What does 'Nouveau riche' refer to?

♦ Nouveau riche:
English meaning: people from a low social class who have recently become very rich and like to show this publicly by spending a lot of money.
Bangla meaning: নব্য ধনী (বিশেষত যারা ধনের জাঁক করে)।

Example: The nouveau riche family moved into the affluent neighborhood, quickly making their presence known with luxury cars and opulent parties.