em‧pe‧ror /ˈempərə $ -ər/ noun [countable]
[Date: 1100-1200; Language: Old French; Origin: empereor, from Latin imperare 'to command']
the man who is the ruler of an empire

[TahlilGaran] Dictionary of Contemporary English ▲

emperor
noun
ADJ. reigning
VERB + EMPEROR crown sb Charlemagne was crowned Emperor on Christmas Day 800 AD.
PREP. under an/the ~ It was under the emperor Justinian that these advances were made.
~ of the emperor of Japan
PHRASES the reign of an emperor during the reign of the last emperor

[TahlilGaran] Collocations Dictionary ▲

king the male ruler of a country, who comes from a royal family:
George III was the king of England at that time.
King Harald V of Norway
queen a woman who rules a country because she is from a royal family, or the wife of a king:
She became queen when she was only 14 years old.
Queen Elizabeth II of the United Kingdom
monarch a king or queen:
The bishops were appointed by the monarch.
monarchy a country that is ruled by a king or queen, or this type of political system:
Britain is a constitutional monarchy.
Some people want the monarchy to be abolished.
prince the son of a king, queen, or prince, or the male ruler of a small country or state:
Prince Rainier of Monaco
The prince will inherit the throne when his father dies.
ruler someone such as a king, who has official power over a country and its people:
the ruler of Babylonia
General Musharraf was the former military ruler of Pakistan.
emperor the ruler of an empire (=group of countries):
the Habsburg emperors of the 19th century
Emperor Hirohito
sovereign formal a king or queen:
It was hoped that a meeting of the two sovereigns would ease tensions between the countries.
regent someone who governs instead of a king or queen, because the king or queen is ill, absent, or still a child:
Edward II left his friend Gaveston as regent.
the crown formal the position of king or queen:
Warwick was a loyal servant of the crown.

[TahlilGaran] English Thesaurus ▲