Nano-
Nano is a unit prefix meaning one billionth. Used primarily with the metric system, this prefix denotes a factor of 10−9 or. It is frequently encountered in science and electronics for prefixing units of time and length.
The prefix derives from the Greek Wiktionary:νᾶνος, meaning "dwarf". The General Conference on Weights and Measures officially endorsed the usage of nano as a standard prefix in 1960.
When used as a prefix for something other than a unit of measure, nano refers to nanotechnology, or means "on a scale of nanometres".
Nanometre(Nanometer)
X-rays have a wavelength ranging from the size of 0.01 nm to 10 nm.Three gold atoms lined up are about one nanometer long.
Human fingernails grow at approximately one nanometer per second.