#constant  a number representing a quantity assumed to have a fixed value in a specified mathematical context; "the velocity of light is a constant"
  supertype:  number  a concept of quantity derived from zero and units; "every number has a unique position in the sequence"
  subtype:  Avogadro's_number__Avogadro_number  the number of molecules in a mole of a substance (approximately 602,250,000,000,000,000,000,000)
  subtype:  Boltzmann's_constant  constant used in the calculation of the ideal gas constant
  subtype:  coefficient  a constant number that serves as a measure of some property or characteristic
     subtype:  absorption_coefficient__coefficient_of_absorption__absorptance  a measure of the rate of decrease in the intensity of electromagnetic radiation (as light) as it passes through a given substance; the fraction of incident radiant energy absorbed per unit mass or thickness of an absorber: "absorptance equals 1 minus transmittance"
     subtype:  drag_coefficient__coefficient_of_drag  the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body
     subtype:  coefficient_of_friction  the ratio of the weight of an object being moved along a surface and the force that maintains contact between the object and the surface
     subtype:  coefficient_of_mutual_induction__mutual_inductance  a measure of the induction between two circuits; the ratio of the electromotive force in a circuit to the corresponding change of current in a neighboring circuit; usually measured in henries
     subtype:  coefficient_of_self_induction__self-inductance  the ratio of the electromotive force produced in a circuit by self-induction to the rate of change of current producing it, expressed in henries
     subtype:  modulus__modulu  (physics) a coefficient that expresses how much of a specified property is possessed by a specified substance
        subtype:  coefficient_of_elasticity__modulus_of_elasticity__elastic_modulus__elasticmodulu  (physics) the ratio of the applied stress to the change in shape of an elastic body
           subtype:  bulk_modulus  the ratio of the change in pressure acting on a volume to the fractional change in volume
           subtype:  modulus_of_rigidity  the coefficient of elasticity for a shearing force
           subtype:  Young's_modulus__young'smodulu  a coefficient of elasticity applicable to the stretching of a wire
     subtype:  coefficient_of_expansion__expansivity  the fractional change in length or area or volume per unit change in temperature at a given constant pressure
     subtype:  coefficient_of_reflection__reflection_factor__reflectance__reflectivity  the fraction of radiant energy that is reflected from a surface
     subtype:  transmittance__transmission  the fraction of radiant energy that passes through a substance
     subtype:  coefficient_of_viscosity__absolute_viscosity__dynamic_viscosity__dynamicviscosity  a measure of the resistance to flow of a fluid under an applied force
     subtype:  weighting__weight  (statistics) a coefficient assigned to elements of a frequency distribution in order to represent their relative importance
  subtype:  cosmological_constant  an arbitrary constant in the equations of general relativity theory
  subtype:  equilibrium_constant__equilibriumconstant  (chemistry) the ratio of concentrations when chemical equilibrium is reached in a reversible reaction (when the rate of the forward reaction equals the rate of the reverse reaction)
     subtype:  dissociation_constant  the equilibrium constant for a reversible dissociation
  subtype:  universal_gas_constant__universalgasconstant__gas_constant__gasconstant__r  (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole
  subtype:  universal_gravitational_constant__universalgravitationalconstant__gravitational_constant__gravitationalconstant__constant_of_gravitation__G  (physics) the universal constant relating force to mass and distance in Newton's law of gravitation
  subtype:  Hubble's_constant__Hubble_constant  (cosmology) the ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer; the reciprocal of the Hubble constant is the age of the universe
  subtype:  ionic_charge__ioniccharge  the charge on an ion is equal to a constant charge e multiplied by an integer from 1 to 15
  subtype:  factor_of_proportionality__constant_of_proportionality  the constant value of the ratio of two proportional quantities x and y; usually written y = kx, where k is the factor of proportionality
     subtype:  Planck's_constant__h  the constant of proportionality relating the energy of a photon to its frequency; approximately 6.626 x 10\-34 joule-second
  subtype:  speed_of_light__light_speed__lightspeed__c  the speed at which light travels in a vacuum; the constancy and universality of the speed of light is recognized by defining it to be exactly 299,792,458 meters per second

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