Translation guide
The English word "ruler" has two main meanings: a measuring tool and a person who governs. This guide covers both, with natural Japanese expressions for each.
ruler (measuring tool)
ruler (person who governs)
General word for a ruler or straightedge used for measuring or drawing lines. Often used in school and office contexts.
Please draw a line with a ruler.
This ruler is 30 centimeters.
Specifically a ruler for measuring length, often a flat strip with markings. Slightly more traditional or formal than 定規.
Measure the length with a ruler.
Loanword from English 'scale', often used for rulers in technical or design contexts, or for measuring tapes.
I use a scale ruler when drawing blueprints.
Technical term for a straight ruler, as opposed to a curved or specialized ruler. Used in drafting.
Draw precise lines with a straight ruler.
A person who rules or governs a country, region, or group; a sovereign or leader.
General term for a ruler, one who rules or controls. Can be used for monarchs, dictators, or any person in power.
He reigned as the ruler of the country.
Emphasizes governing or administering a territory. More formal and often used in historical or political contexts.
Specifically a monarch, such as a king, queen, or emperor. Implies hereditary sovereignty.
A person in charge of administration; a statesman or political ruler. Often used in discussions of governance.
定規 is the most common word for a ruler used in school or office. 物差し specifically refers to a measuring ruler, often a flat wooden or plastic strip, and can sound slightly more traditional. In everyday conversation, 定規 is usually sufficient.
While 支配者 is a direct translation, it can sound harsh or authoritarian. In contexts where you mean a monarch or leader, consider 君主 or 統治者 depending on the nuance. For democratic leaders, 指導者 (leader) might be more appropriate.
I need a ruler to draw a straight line.
The ruler of the kingdom was wise.
その統治者は公正な政策を行った。
The ruler implemented fair policies.
その国の君主は絶大な権力を持っていた。
The ruler of that country had immense power.
Rulers should listen to the voice of the people.