planck's constant

English Thesaurus

1. the constant of proportionality relating the energy of a photon to its frequency; approximately 6.626 x 10^-34 joule-second (noun.quantity)

hypernym	:	constant of proportionality, factor of proportionality,
definition	:	the constant value of the ratio of two proportional quantities x and y; usually written y = kx, where k is the factor of proportionality (noun.quantity)