Metrology Glossary – N

At J.A. King, we strive to educate our team and our customers so we can all make informed decisions and improve quality. Having information at our fingertips is the best way to do that. We have compiled a list of the most common terminology within the precision measurement industry, backed by our experts with years within our industry.

Precision Measurement Glossary of Terms

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N-Max (Maximum Number of Scale Division)

Maximum number of divisions a scale has. A division is the smallest change that will be displayed by the scale


Prefix used in the SI measurement system to denote a division of one billionth (0.000000000001) of a unit of measure.

National Conference of Weights and Measures (NCWM)

A non-profit organization whose mission is “To advance a healthy business and consumer climate through the development and implementation of uniform and equitable weights and measures standards using a consensus building process.”

National Electrical Manufacturers Association (NEMA)

The largest trade association of electrical equipment manufacturers in the United States

National Institute for Standards and Technology (NIST)

Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Department of Commerce. NIST’s mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life. Calibration providers in the U.S. ensure the accuracy of their standards by establishing and documenting a chain of traceability to the primary standards housed and maintained at NIST.

National Pipe Thread Taper (NPT)

National Pipe Thread, tapered, is a system of standard measurements applied to threaded connections used in plumbing pressure systems. Many kinds of fittings including pressure gauges and fittings on thermometer probes may be sized according to NPT standard sizes from 1/8 inch to 1 inch.

National Type Evaluation Program (NTEP)

The National Conference on Weights and Measures issues an NTEP Certificate of Conformance following successful completion of an evaluation of a device. It indicates that the device(s) described in the Certificate is/are capable of meeting applicable requirements of the NIST Handbook 44 for legal-for-trade scales.

Negative Logic

If the signal that activates the circuit (the 1 state) has a voltage level that is more NEGATIVE than the 0 state, then the logic polarity is considered to be NEGATIVE.


A standard from the National Electrical Manufacturers Association, which defines enclosures with protection against dirt, dust, splashes by non-corrosive liquids and salt spray.


A standard from the National Electrical Manufacturers Association, which defines explosion-proof enclosures for use in locations classified as Class I, Groups A, B, C, or D, as specified in the National Electrical Code.


Case An older US case standard for panel meters, which requires a panel cutout of 3.93 x 1.69″

Neutral Salt Spray (NSS)

An accelerated corrosion test in which the test solution pH value is at 6.5-7.

Nominal Load Capacity

The maximum weight a load cell is designed to measure under normal conditions

Non-Latching Relays

Relays that maintain their state only while being actuated and return to a known state when power to the actuating signal is interrupted.


In an ideal system, the input-out relationship is linear (i.e., straight line). Any departure from straight line is expressed as non-linearity.

Non-volatile Memory

A storage system where memory in a computer remains even if the computer is turned off

Normal Mode

Identifies undesired signals that are not common to both input terminals of differential amplifier. Also known as Series Mode.

Normal-Mode Rejection (NMR)

The ability of a panel meter to filter out noise superimposed on the signal and applied across the SIG HI to SIG LO input terminals. Normally expressed in dB at 50/60 Hz.

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