millimeetri

Millimeeter, abbreviated mm, is a unit of length in the metric system. It is defined as one thousandth of a metre: 1 mm = 0.001 m. The millimetre is a submultiple of the metre and is widely used for measuring small dimensions in science, engineering, manufacturing, and everyday objects.

One can relate millimetres to other common units: 10 mm equals 1 centimetre, 1000 mm equals 1 metre. In the imperial system, 1 mm is exactly 0.03937 inches, since 1 inch equals 25.4 millimetres.

Measuring devices such as calipers, micrometers, and coordinate measuring machines use millimetres as a primary unit, with many instruments offering subdivisions to tenths or hundredths of a millimetre.

Common uses include specifying thicknesses of paper and films, dimensions in mechanical drawings, and the thickness of coatings. The millimetre is part of the International System of Units (SI) and is the standard unit for measuring small lengths in most countries.

History: The millimetre emerged with the metric system in the 18th–19th centuries as the metre was adopted as the base unit. It remains the standard subunit of length in SI today.