noun
ruler; straightedge
A measuring and drawing tool for drawing straight lines or measuring length. Common in school, office, and workshop contexts.
定規で線を引いてください。
Please draw a line with a ruler.
この定規は30センチまで測れます。
This ruler can measure up to 30 centimeters.
Standard kanji spelling for a ruler or straightedge.
Uncommon variant; 定規 is overwhelmingly preferred.
定 (fixed, determined) + 規 (standard, rule). The compound originally referred to a fixed standard or rule, later applied to the physical measuring tool.