from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The constant of proportionality relating the energy of a photon to the frequency of that photon. Its value is approximately 6.626 × 10-34 joule-seconds.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the constant of proportionality (symbol h), relating the energy and frequency of a photon (6.626 x 10-34 joule-seconds); also related to the indeterminacy limit in the Heisenberg uncertainty principle; the quantum of action
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the constant of proportionality relating the energy of a photon to its frequency; approximately 6.626 x 10^-34 joule-second
After Max Karl Ernst Ludwig Planck.(American Heritage® Dictionary of the English Language, Fourth Edition)
Named for Max Planck (1858–1947), German theoretical physicist, who discovered it in 1900. (Wiktionary)