1) Serena Williams is an American professional tennis player widely regarded as one of the greatest athletes in the sport. She has won numerous Grand Slam titles and Olympic gold medals and has become an influential figure both on and off the tennis court.

2) The word "bank" comes from the Italian word "banco," which means bench. In medieval Italy, bankers conducted their business on benches in the marketplace.

3) The European Union (EU) is a supranational organization comprising 27 member states that cooperate on various issues, including trade, economic integration, and common policies, while preserving individual national sovereignty.

4) The Dow Jones Industrial Average (DJIA) is a stock market index that tracks the performance of 30 large, publicly owned companies in the United States.