The nanometre is a unit of length and is a multiple of the SI unit metre. It uses the symbol nm.
1 nm is equal to one one-billionth of a metre. (Nano is the prefix for one billionth). It is used to express dimensions on an atomic scale for example a helium atom has a radius of approximately 0.03nm.
The nanometre was previously known as the millimicrometre (or the millimicron).
The centimetre is a unit of length and is a multiple of the metre; an SI derived unit. It has the symbol cm.
A centimetre is equal to 0.01m. It is also ≈ 0.3937in.
Centimetres are used in maps to scale up conversions to real world measurements.