- a person who rules or commands
- Also called: rule a strip of wood, metal, or other material, having straight edges graduated usually in millimetres or inches, used for measuring and drawing straight lines
WordReference Random House Learner's Dictionary of American English © 2026
rul•er /ˈrulɚ/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2026- one who rules or governs, as a king, queen, president, etc.
- Weights and MeasuresAlso, rule. a strip of wood or other material that has a straight edge and is marked off in inches or centimeters, used for drawing lines and measuring.
rul•er
(ro̅o̅′lər),USA pronunciation n.
- a person who rules or governs;
sovereign. - Weights and MeasuresAlso, rule. a strip of wood, metal, or other material having a straight edge and usually marked off in inches or centimeters, used for drawing lines, measuring, etc.
- a person or thing that rules paper, wood, etc.
- Astrologythe planet primarily associated with any sign of the zodiac or any house of the horoscope:The ruler of Aries is Mars. The ruler of Taurus is Venus.
- 1325–75; Middle English; see rule, -er1
Collins Concise English Dictionary © HarperCollins Publishers::
ruler /ˈruːlə/ n
'ruler' also found in these entries (note: many are not synonyms or translations):
Abbas I
- Abd al-Malik ibn Marwan
- Abdul-Hamid II
- Abdullah
- Abdullah II
- absolute
- Abu-Bekr
- accurate
- Akhenaten
- Alaric
- Albert
- Albert I
- Albert II
- Alboin
- Alexander I
- Alexander II
- Alexander III
- Alexandra
- Alexis Mikhailovich
- Alexius I Comnenus
- Alfonso VI
- Alfonso XIII
- Ali
- Ali Pasha
- Amanullah Khan
- anarchy
- Anne
- Anne of Austria
- Antigonus I
- Antiochus III
- Antiochus IV
- Antoninus Pius
- arbitrary
- -arch
- archon
- Artaxerxes I
- Artaxerxes II
- Asantehene
- Ashurbanipal
- Atahualpa
- Athelstan
- Aurangzeb
- Aurelian
- autocrat
- autocratic
- Baber
- Baldwin I
- Baliol
- Basil I
- Baudouin I