The nanometre (international spelling as used by the
International Bureau of Weights and Measures The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ...

International Bureau of Weights and Measures
symbol: nm) or nanometer (
American spelling Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variations being British and America ...

American spelling
) is a
unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piece of action (or beat) in a theatrical presentation Music * ''Unit'' (album ...

length Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the Internati ...

in the
metric system A metric system is a system of measurement that succeeded the decimalised system based on the metre introduced in France in the 1790s. The historical development of these systems culminated in the definition of the International System of Unit ...

metric system
, equal to one
billionthOne billionth is the reciprocal of a billion, which means it has one of two definitions depending on whether the ''long scale'' or ''short scale'' definition is being used. Short scale In the short (or American) scale, a billionth is equal to 0.000 ...

short scale The long and short scales are two of several naming systems for integer powers of ten which use some of the same terms for different magnitudes. For whole numbers smaller than 1,000,000,000 (109), such as one thousand or one million, the two sca ...

short scale
) of a
metre The metre (Commonwealth spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure", and cognate with Sanskrit , meaning "measured") is the base unit of length in the Internation ...

( m). One nanometre can be expressed in
scientific notation Scientific notation is a way of expressing numbers that are too large or too small (usually would result in a long string of digits) to be conveniently written in decimal form. It may be referred to as scientific form or standard index form, or s ...

scientific notation
as , in
engineering notation Engineering notation or engineering form is a version of scientific notation in which the exponent of ten must be divisible by three (i.e., they are powers of a thousand, but written as, for example, 106 instead of 10002). As an alternative to writi ...

engineering notation
as , and as simply metres.


The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is of a
micron The micrometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is an SI derived unit of length equalling (SI standard pre ...

(micrometre), and was often denoted by the symbol mµ or (more rarely and confusingly, since it logically should refer to a ''millionth'' of a micron) as µµ.


The name combines the
SI prefix A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The prefix '' ...

SI prefix
''nano-'' (from the
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic period ...

Ancient Greek
, ', "dwarf") with the parent unit name ''metre'' (from Greek , ', "unit of measurement"). When used as a
prefix A prefix is an affix which is placed before the stem of a word. Adding it to the beginning of one word changes it into another word. For example, when the prefix ''un-'' is added to the word ''happy'', it creates the word ''unhappy''. Particularly ...

for something other than a unit of measure (as in "nanoscience"), nano refers to
nanotechnology Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal of pr ...

, or phenomena typically occurring on a scale of nanometres (see
nanoscopic scale 300px| A ribosome is a [[biological machine that utilizes nanoscale [[protein dynamics The nanoscopic scale (or nanoscale) usually refers to structures with a length scale applicable to nanotechnology, usually cited as 1–100 nanometers. A nan ...

nanoscopic scale


The nanometre is often used to express dimensions on an atomic scale: the diameter of a [[helium atom, for example, is about 0.06 nm, and that of a [[ribosome is about 20 nm. The nanometre is also commonly used to specify the [[wavelength of [[electromagnetic radiation near the visible part of the
spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without steps, across a Continuum (theory)|continuum. The word was first used scientifically in optics to describe the ...

: visible light ranges from around 400 to 700 nm.Hewakuruppu, Y., et al.,
Plasmonic " pump – probe " method to study semi-transparent nanofluids
', Applied Optics, 52(24):6041-6050
ångström The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.me ...

, which is equal to 0.1 nm, was formerly used for these purposes, but is still used in other fields. Since the late 1980s, in usages such as the
32 nm The 32 nm node is the step following the 45 nm process in CMOS (MOSFET) semiconductor device fabrication. "32-nanometre" refers to the average half-pitch (i.e., half the distance between identical features) of a memory cell at this technology l ...

32 nm
and the
semiconductor node Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically the metal–oxide–semiconductor (MOS) devices used in the integrated circuit (IC) chips that are present in everyday electrical and electro ...

semiconductor node
, it has also been used to describe typical feature sizes in successive generations of the for
miniaturization Miniaturization (Br.Eng.: ''Miniaturisation'') is the trend to manufacture ever smaller mechanical, optical and electronic products and devices. Examples include miniaturization of mobile phones, computers and vehicle engine downsizing. In electro ...

in the
semiconductor industry The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors. It formed around 1960, once the fabrication of semiconductor devices became a viable business. The industry's annual semiconductor ...

semiconductor industry

See also

* * the nanometre symbol (U+339A ''SQUARE NM'')


External links

Near-field Mie scattering in optical trap nanometry
{{SI units of length
Category:Units of length Length Category:Length {{CatAutoTOC ...

Category:Units of length