From Wikipedia, the free encyclopedia.
A micrometre (American English: micrometer), symbol µm is an SI unit of length. It is defined as one millionth of a metre (or 1 × 10-6 m). The letter µ is the Greek letter mu.
Some people (especially in astronomy) use the old name micron and/or the solitary symbol µ, for the same thing, even though it is officially discouraged.
The micrometre is a common unit of measurement when examining the wavelengths of infrared radiation.
For a list of objects on the order of one to a 10 micrometres, see 1 E-6 m.