A nanometre (American spelling: nanometer, symbol nm) (Greek: νάνος, nanos, dwarf; μετρώ, metrό, count) is a unit of length in the metric system, equal to one billionth of a metre (for example, one millionth of a millimetre), which is the current SI base unit of length. It can be written in scientific notations as 1×10−9 m (engineering notation) or (exponential notation) — both meaning . It is one of… (More on Nanometre)