National Institute of Science and Technology: An independent agency of the U.S. Department of Commerce charged with the improvement and maintenance of standards.

National Research Council of Canada: An independent agency of the Canadian Government charged with the improvement and maintenance of standards.

Neon: An inert element which is a gas at room temperature.

Neutron: An elementary particle with 0 charge and mass about equal to a proton.

Neutrino: An elementary particle with zero charge and zero mass.

Newton: A unit of force equal to the force that imparts an acceleration of 1 m/sec/sec to a mass of 1 kilogram.

Newtonian Fluid: A fluid whose absolute viscosity is the same for all values of shear stress.

Nominal Value: This is normally the value indicated by the manufacture.

Nonconformity: Nonfulfillment of a specified requirement.

Nonlinear: Pertaining to a response which is not directly or inversely proportional to a given variable.

Normally Closed (NC) Switch: A switch in which the contracts are closed without any external force acting upon it.

Normally Open (NO) Switch: A switch in which contracts are open when no external forces act upon the switch.

Null Method: Any method of measurement in which the reading is taken at zero.