1) The term "bull market" refers to a period of rising stock prices, while a "bear market" refers to a period of falling stock prices.

2) The President of the United States serves as the head of state and the head of government, responsible for leading the executive branch and representing the nation domestically and internationally.

3) The concept of gravity was famously described by Sir Isaac Newton after an apple fell on his head.

4) The Olympic motto is "Citius, Altius, Fortius," which is Latin for "Faster, Higher, Stronger."