The upper social class — the wealthy and influential segment of society (the elite).
彼は上流階級の出身で、家は代々資産家だ。
He comes from the upper class; his family has been wealthy for generations.
上流階級の人々はしばしば別荘を所有している。
People of the upper class often own vacation homes.
そのパーティーには上流階級の人々しか招かれなかった。
Only members of the upper class were invited to that party.