Micrometre
SI unit of length equal to one millionth of a metre or 1/1000th of a millimetre
A micrometre (the American spelling is micrometer; symbol is µm) is a unit of length in the SI measurement system. It can also be called a micron. It is one millionth of a metre. A micrometre is often used as a measurement for small things like bacteria. Like the Angstrom it is used for radiation in or near the visible spectrum.
