Con″stant, n. 1. (Astron.) A number whose value, when ascertained (as by observation) and substituted in a general mathematical formula expressing an astronomical law, completely determines that law and enables predictions to be made of its effect in particular cases.
2. (Physics) A number expressing some property or condition of a substance or of an instrument of precision; as, the dielectric constant of quartz; the collimation constant of a transit instrument.
Aberration constant, orConstant of aberration(Astron.), a number which by substitution in the general formula for aberration enables a prediction to be made of the effect of aberration on a star anywhere situated. Its value is 20″.47. — Constant of integration(Math.), an undetermined constant added to every result of integration. — Gravitation constant(Physics), the acceleration per unit of time produced by the attraction of a unit of mass at unit distance. When this is known the acceleration produced at any distance can be calculated. — Solar constant(Astron.), the quantity of heat received by the earth from the sun in a unit of time. It is, on the C. G. S. system, 0.0417 small calories per square centimeter per second. Young.