constant

/ˈkɑnstənt/

/ˈkɒnstənt/

Other forms: constants

Think of something or someone that does not change as constant. A classmate's constant drumming on the table with his fingers could be a constant source of annoyance.

Constant derives from Latin verb meaning "to stand with," so something constant is continually standing with you and not wavering. You may be thankful for the constant companionship of your dog but not necessarily for your teacher's constant homework assignments. In math and science, a constant is a number that is fixed and known, unlike a variable which changes with the context. That idea crosses over to real life. If a friend is a constant in your life, that means they have always been with you and there for you.

Definitions of constant

1. adjective

   uninterrupted in time and indefinitely long continuing
   “in constant pain”

   synonyms: ceaseless, incessant, never-ending, perpetual, unabating, unceasing, unremitting

   continuous, uninterrupted

   continuing in time or space without interruption
2. adjective

   unvarying in nature
   “maintained a constant temperature”

   synonyms: changeless, invariant, unvarying

   invariable

   not liable to or capable of change
3. adjective

   steadfast in purpose or devotion or affection
   “a man constant in adherence to his ideals”

   “constant as the northern star”

   synonyms:

   unchangeable

   not changeable or subject to change

   staunch, steadfast, unswerving

   firm and dependable especially in loyalty

   unfailing, unflagging

   unceasing

   faithful

   steadfast in affection or allegiance

   stable

   resistant to change of position or condition

   invariable

   not liable to or capable of change

   antonyms:

   inconstant

   likely to change frequently often without apparent or cogent reason; variable

   changeable, changeful

   such that alteration is possible; having a marked tendency to change

   false, untrue

   (used especially of persons) not dependable in devotion or affection; unfaithful

   fickle, volatile

   marked by erratic changeableness in affections or attachments

   unfaithful

   not true to duty or obligation or promises

   unstable

   lacking stability or fixity or firmness

   variable

   liable to or capable of change

   volatile

   evaporating readily at normal temperatures and pressures
4. noun

   a quantity that does not vary
   synonyms: constant quantity, invariable

   types:

   parameter, parametric quantity

   a constant in the equation of a curve that can be varied to yield a family of similar curves

   degree of freedom

   one of the minimum number of parameters needed to describe the state of a physical system

   type of:

   quantity

   the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable
5. noun

   a number representing a quantity assumed to have a fixed value in a specified mathematical context
   “the velocity of light is a constant”

   types:

   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)

   R, gas constant, universal gas constant

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

   G, constant of gravitation, gravitational constant, universal gravitational constant

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

   Hubble constant, Hubble parameter, Hubble's constant, Hubble's parameter

   (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 Hubble constant is not actually a constant, but is regarded as measuring the expansion rate today

   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

   c, light speed, speed of light

   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

   absorptance, absorption coefficient, coefficient of absorption

   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

   coefficient of drag, drag coefficient

   the ratio of the drag on a body moving through air to the product of the velocity and the surface area of the body

   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

   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

   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

   modulus

   (physics) a coefficient that expresses how much of a specified property is possessed by a specified substance

   coefficient of expansion, expansivity

   the fractional change in length or area or volume per unit change in temperature at a given constant pressure

   coefficient of reflection, reflectance, reflection factor, reflectivity

   the fraction of radiant energy that is reflected from a surface

   transmission, transmittance

   the fraction of radiant energy that passes through a substance

   absolute viscosity, coefficient of viscosity, dynamic viscosity

   a measure of the resistance to flow of a fluid under an applied force

   weight, weighting

   (statistics) a coefficient assigned to elements of a frequency distribution in order to represent their relative importance

   dissociation constant

   the equilibrium constant for a reversible dissociation

   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

   type of:

   number

   a concept of quantity involving zero and units