Millimetrit

Millimetrit is the Finnish plural form of the metric unit millimetre (symbol mm). A millimetre is a unit of length in the metric system equal to one thousandth of a metre (0.001 m). In the International System of Units (SI), the millimetre is a derived unit, obtained by dividing the metre by 1000. Practically, 1 centimetre equals 10 millimetres and 1 metre equals 1000 millimetres. The millimetre is commonly used for measuring small dimensions, thicknesses, gaps, and tolerances in science, engineering, manufacturing, and everyday contexts.

Usage and application vary by field. For example, in electronics and manufacturing, dimensions such as component sizes, PCB traces, or material thicknesses are often specified in millimetres. In construction and architecture, millimetres are used for precise measurements and tolerances. In Finland, as in many other countries, the plural form millimetrit is used when referring to several millimetres, while the symbol mm remains the standard notation in technical writing.

History and standardization: the metre was established as the basic SI unit, with subsequent refinements to its definition (notably a 1983 redefinition based on the speed of light). The millimetre, as a decimal subdivision of the metre, has been widely adopted alongside centimetres and metres for practical measurements in science and industry.

See also: millimetre, centimetre, metre, SI units.