A nanometer (nm) is a unit of length in the metric system, defined as one billionth (10-9) of a meter (m). The meter is the base unit of length in the International System of Units (SI), making the ...

Another way to think about it: if a nanometer were the size of a marble, a micron would be the size of a basketball. Since wavelengths of light in the visible spectrum range from 400-700 ...