Nano-

{{Short description|SI prefix denoting 10 to the -9th power}}

{{Other uses|Nano (disambiguation){{!}}Nano}}

{{More citations needed|date=January 2020}}

{{Wiktionary|nano-}}

Nano (symbol n) is a unit prefix meaning one billionth. Used primarily with the metric system, this prefix denotes a factor of 10⁻⁹ or {{Gaps|0.000|000|001}}. It is frequently encountered in science and electronics for prefixing units of time and length.

;Examples:

• Three gold atoms lined up are about one nanometer (nm) long.
• If a toy marble were scaled down to one nanometer wide, Earth would scale to about {{convert|1|m|ft|sp=us}} wide.{{Cite web|url=https://www.nano.gov/nanotech-101/what/nano-size|title=Size of the Nanoscale|publisher=National Nanotechnology Initiative|access-date=2020-05-14}}
• One nanosecond (ns) is about the time required for light to travel 30 cm in air, or 20 cm in an optical fiber.
• One nanometer per second (nm/s) is approximately the speed that a fingernail grows.

The prefix derives from the Greek {{lang|grc|νᾶνος}} (Latin {{lang|la|nanus}}), meaning "dwarf". The General Conference on Weights and Measures (CGPM) 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 (as for example in words like "nanoscience"), nano refers to nanotechnology, or means "on a scale of nanometres" (nanoscale).

{{SI prefixes (infobox)}}