In ISO standards, what does “µm” stand for?

The term "µm" stands for micrometer, which is a unit of length in the metric system equal to one-millionth of a meter. It is commonly used in various scientific fields, including biology, materials science, and engineering, to measure small distances or sizes, such as the dimensions of cells or particles. The micrometer is essential in contexts where precision measurements at the microscopic level are necessary, thus justifying its use in ISO standards that frequently pertain to quality and measurement.

The other options represent different units of measurement that do not correspond to "µm." For instance, millimeters, micrograms, and meters each have their specific meanings and are unsuitable for representing the micrometer. In summary, understanding the importance and application of the micrometer assists professionals in fields where precision at small scales is crucial, aligning with ISO standards that ensure quality and accuracy throughout various industries.