Planck's constant: Meaning and Definition of

Planck's' con'stant

Pronunciation: [key]
— Physics. Physics.
  1. the fundamental constant of quantum mechanics, expressing the ratio of the energy of one quantum of radiation to the frequency of the radiation and approximately equal to 6.624 × 10− erg-seconds. Symbol: h&hasp;
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.