A nanometre (nm) is a unit of length in the metric system, equal to one billionth of a metre (1 nm = 1 × 10⁻⁹ metres). It is commonly used to measure extremely small distances, particularly at the atomic and molecular scale.
- In the context of light and electromagnetic radiation, a nanometre is often used to describe wavelengths of visible light.
The wavelength of visible light ranges from about 700 nm (red) to 400 nm (violet). - Nanometres are also used to measure components like the thickness of materials, the size of particles in nanotechnology, and the spacing between atoms in a crystal lattice.