quantity - something that has a magnitude and can be represented in mathematical expressions by a constant or a variable

parameter, parametric quantity - a constant in the equation of a curve that can be varied to yield a family of similar curves

number - a concept of quantity derived from zero and units; "every number has a unique position in the sequence"

Avogadro number, Avogadro's number - the number of molecules in a mole of a substance (approximately 602,250,000,000,000,000,000,000)

Boltzmann's constant - constant used in the calculation of the ideal gas constant

coefficient - a constant number that serves as a measure of some property or characteristic

cosmological constant - an arbitrary constant in the equations of general relativity theory

equilibrium constant - (chemistry) the ratio of concentrations when equilibrium is reached in a reversible reaction (when the rate of the forward reaction equals the rate of the reverse reaction)

gas constant, universal gas constant, R - (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole

constant of gravitation, gravitational constant, universal gravitational constant, G - (physics) the universal constant relating force to mass and distance in Newton's law of gravitation

Hubble constant, Hubble's 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

ionic charge - the charge on an ion is equal to a constant charge e multiplied by an integer from 1 to 15

constant of proportionality, factor 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

light speed, speed of light, 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

invariable - not liable to or capable of change; "an invariable temperature"; "an invariable rule"; "his invariable courtesy"

continual - seemingly without interruption; chiefly restricted to what recurs regularly or frequently in a prolonged and closely spaced series; "the continual banging of the shutters"

unchangeable - not changeable or subject to change; "a fixed and unchangeable part of the germ plasm"-Ashley Montagu; "the unchangeable seasons"; "one of the unchangeable facts of life"

faithful - steadfast in affection or allegiance; "years of faithful service"; "faithful employees"; "we do not doubt that England has a faithful patriot in the Lord Chancellor"

stable - resistant to change of position or condition; "a stable ladder"; "a stable peace"; "a stable relationship"; "stable prices"

invariable - not liable to or capable of change; "an invariable temperature"; "an invariable rule"; "his invariable courtesy"

continuous, uninterrupted - continuing in time or space without interruption; "a continuous rearrangement of electrons in the solar atoms results in the emission of light"- James Jeans; "a continuous bout of illness lasting six months"; "lived in continuous fear"; "a continuous row of warehouses"; "a continuous line has no gaps or breaks in it"; "moving midweek holidays to the nearest Monday or Friday allows uninterrupted work weeks"