Pronunciation: [mˈɛtə͡l ɹˈuːl] (IPA) 
The correct spelling of the word "metal rule" is /ˈmɛtəl rul/. The word "metal" is pronounced as /ˈmɛtəl/ with a short "e" sound and the letter "t" pronounced as a voiceless dental fricative. The word "rule" is pronounced as /rul/ with a long "u" sound and the letters "r" and "l" clearly pronounced. The two words together refer to a length measuring tool made of metal, commonly used in carpentry, engineering, and construction.
A metal rule, also referred to as a steel ruler or metal measuring ruler, is a standardized measuring tool predominantly composed of metal, particularly steel. It possesses a rigid and slender shape, typically having a length ranging from a few centimeters up to a meter, and bears calibrated markings along its edge. These distinctive markings depict units of measurement, often in millimeters, centimeters, and inches, facilitating precise and accurate measurements in various fields of work.
The construction of a metal rule involves the utilization of a sturdy metal, usually stainless steel, due to its resilience against deformation, corrosion, and wear. This ensures the ruler's durability and longevity even under rigorous and demanding conditions. The inherent rigidity of the metal structure grants the rule stability and steadiness, further enhancing the reliability of measurement results.
Metal rules are employed in diverse applications spanning various industries, including woodworking, construction, engineering, and general home use. They are particularly valuable for tasks that necessitate exact measurements, such as marking and cutting materials to specific dimensions, verifying alignment and straightness, determining angles, and inspecting clearance.
Compared to other measuring tools like tape measures or rulers made from less robust materials, metal rules offer superior accuracy, stability, and durability, making them indispensable instruments for professionals and hobbyists requiring precise measurements in their respective domains.
The word "metal" derives from the Old English word "metall", which came from the Latin word "metallum". In Latin, "metallum" originally referred to a mine or quarry, but later extended its meaning to include metallic substances.
The word "rule" comes from the Old English word "rǖl", which originated from the Latin word "regula", meaning straight stick or bar for measurement. "Regula" also had the broader meaning of a pattern or guide to follow.
Therefore, the etymology of "metal rule" suggests that it combines the Middle English usage of "metal" meaning "substance made of metal", and "rule" referring to a straight stick or bar used for measurement or as a guide.
