Nanometer (nm)
Definition: Nanometer (symbol: nm) na one billionth of meter (0.000000001 m or 10^-9 m). Na metric unit wey dem dey use for extremely small length.
History/origin: Nanometer show up for scientific use of metric system as researchers need practical names for very small scales. E become especially common for physics, chemistry, optics, and semiconductor manufacturing.
Current use: Dem dey use nanometers to describe wavelength of light, dimensions of molecules, atomic‑scale structures, and fabrication sizes for electronics and materials science.