Nanometre

The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American spelling) is a unit of length in the metric system, equal to one billionth (short scale) of a metre (0.000000001 m). One nanometre can be expressed in scientific notation as 1×10−9 m, and as 1/1000000000 metres.