Na

Na
Sodium is a soft, silvery coloured metal which, like other members of the alkali group of metals, is extremely reactive.
Na2O
Chemical formula for Sodium Oxide.
Na2O2
Chemical formula for Sodium Peroxide.
NaBr
Chemical formula for Sodium I Bromide.
NACA
Abbreviation of National Advisory Committee for Aeronautics.
NACA Duct
A distinctively shaped inlet that is flush and begins with a narrow, shallow inset and becomes progressively wider and deeper.
NaCl
Chemical formula for quartz.
Nadir
The point on the celestial sphere directly below an observer, diametrically opposite the zenith.
NaF
Chemical formula for Sodium I Fluoride.
Nafion

C7HF13O5S . C2F4

A sulfonated tetrafluoroethylene based fluoropolymer-copolymer.

Nagel Point
In a triangle, the lines from the vertices to the points of contact of the opposite sides with the excircles to those sides meet in a point called the Nagel point.
NaH
Chemical formula for Sodium Hydride.
NaI
Chemical formula for Sodium I Iodide.
Nail Hammer
A hammer designed to hit the head of nails and usually has a claw device which allows for the removal of nails.
Nameplate Rating
The full-load continuous rating of a generator or other electrical equipment under specified conditions as designated by the manufacturer, and written on the nameplate.
Nand Gate
Gate whose output is 0 when both input are 1 and 1 in all other cases.
nano
Prefix representing a multiplication of 10-9. From the ancient Greek word "nanos" or "dwarf".
NaNO3
Chemical formula for Sodium Nitrate.
nanoampere
One billionth of an ampere.
Nanometre
Abbreviated as nm, unit of length equal to 10-9 metres, and equal to 10 Å (Angstroms).
Nanosecond
One billionth of a second, 10-9 s.
nanovolt
One billionth of a volt.
NaO2
Chemical formula for Sodium I Oxide.
NaO3Si
Chemical formula for Sodium Silicate.
NaOCl
Chemical formula for Sodium Hypochlorite.
NaOH
Chemical formula for Sodium Hydroxide.
Naphtha
Volatile solvent distilled from petroleum.
Naphthyleneethylene
Another name for Acenaphthene.
Napier, John
British mathematician and inventor of the logarithm.
Napierian Logarithm
Another name for the Natural or Common Logarithm.
Narthex
An enclosed passage from the nave to the main entrance of a church.
NASA
Abbreviation of National Aeronautics and Space Administration.
National Advisory Committee for Aeronautics
Formed on March 3, 1915, with a charter to supervise and direct the scientific study of the problems of flight, with a view to their practical solution.
National Aeronautics and Space Administration
NASA was formed from the National Aeronautics and Space Act of 1958.
National Electrical Code
The most commonly referenced general electrical standard in the United States.
National Institute for Occupational Safety and Health
Providing National and World Leadership to Prevent Workplace Illnesses and Injuries
National Institute for Standards and Technology
An agency within the US department of commerce that promotes economic growth through the application of technology, measurement and standards.
National Physical Laboratory
National measurement standards laboratory for the UK.
Nato Alphabet
Used when communicating over the radio to ensure there is no miscommunication of important information.
Natrium
Latin for sodium, hence the symbol Na.
Natural Abundance
The average fraction of atoms of a given isotope of an element on Earth.
Natural Base of Logarithms
e = 2.71828
Natural Convection
Movement of a fluid caused only by temperature differences.
Natural Frequency
The frequency of free vibration of a system.
Natural Gas
The cleanest fossil fuel, and hence a potential short-term aid to slowing climate change.
Natural Gas Distribution System
This term generally applies to mains, services, and equipment that carry or control the supply of natural gas from a point of local supply, up to and including the sales meter.
Natural Gas Vehicle
Vehicles that are powered by compressed or liquefied natural gas.
Natural Heat
A term that has generally referred to the heat produced within the body, usually the heat produced by the heart and the circulatory system.
Natural Heat Convection
If the flow of gas away from a hot object starts by itself it is called natural convection. However, if the gas is forced past the object it is called forced convection.
Natural Horizon
The line-of-sight horizon.
Natural Law
Natural laws summarize patterns that recur in a large amount of data.
Natural Logarithm
Logarithm in which the base is e.
Natural Number
Any one of the numbers 1, 2, 3, 4, 5, ..
Naturally Aspirated
An engine that draws air in without the assistance of a supercharger or turbocharger.
Nautical Chain
A unit of length equal to 15 feet.
Nautical Mile
The average distance on the earth's surface subtended by one minute of latitude.
Nautical Year
Also known as a Tropical Year.
Naval Brass
A brass made with 60% copper 40% zinc with 1% tin added for extra corrosion resistance.
Nave
The principal area of a church, extending from the main area to the transept.
Navier Stokes Codes
Computer software that contains the mathematical equations of motion for a viscous fluid.
Navier Stokes Equation
The primary equation of computational fluid dynamics, relating pressure and external forces acting on a fluid to the response of the fluid flow.