μm
Micrometer
A micrometer (also called micron) is a unit of length equal to one millionth of a meter (0.000001 m) or one thousandth of a millimeter. It is used in science and technology for measuring microscopic objects like cells, bacteria, and semiconductor features.
History
The micrometer was introduced as technology advanced enough to measure such small dimensions. The term 'micron' was officially revoked as an SI unit name in 1967, with 'micrometer' becoming the preferred term. However, 'micron' remains widely used in industry.