1. A unit of length equal to one billionth of a metre (10⁻⁹ m), used especially in measuring atomic and molecular dimensions.
Usage: Also spelled nanometer in U.S. English.; Commonly used in physics, chemistry, and nanotechnology.

Examples

• The diameter of a human hair is approximately 100,000 nanometres.
• Nanotechnology works at the scale of nanometres and smaller.
• A single gold atom measures about 0.3 nanometres across.
• The wavelength of visible light ranges from about 400 to 700 nanometres.
• Scientists use electron microscopes to observe structures measured in nanometres.