ruler
n. countable A1 Beginner US //ˈɹuɫɝ// UK //ɹˈuːlɐ// ruler
n. a flat, straight tool used for measuring length or drawing straight lines. It usually has marks for inches or centimeters along the edge.
n. a strip of wood, metal, or plastic with a straight edge and graduated markings used for measuring distance or ruling lines.
Use a ruler to draw a straight line.
The student pulled a plastic ruler from her pencil case to measure the width of the textbook.
Architects often prefer steel rulers for their durability and precision when drafting manual sketches on heavy paper.
From Middle English reuler; equivalent to rule + -er.
Usage
Commonly used with the verbs 'use' or 'measure'.