Emperor (noun)

1. A ruler of an empire, typically an autocrat with great power.
2. The male ruler of an empire.

Origin:

From old french emperere, from latin imperator, from imperare ("to command"), from in- ("in") + parare ("to prepare").

Examples:

1. Napoleon Bonaparte was the first emperor of the French.
2. The emperor of Japan is a largely ceremonial figure.
3. The emperor of the Roman Empire was Augustus Caesar.
4. The sun was worshiped as the emperor of the sky in ancient cultures.
5. The emperor was seen as the son of heaven in ancient China.