Planck's constant

noun

variants or less commonly Planck constant
: a constant that gives the unvarying ratio of the energy of a quantum of radiation to its frequency and that has an exact value of 6.62607015 × 10−34 joule seconds
symbol h

Word History

Etymology

Max K. E. L. Planck

First Known Use

1910, in the meaning defined above

Time Traveler
The first known use of Planck's constant was in 1910

Dictionary Entries Near Planck's constant

Cite this Entry

“Planck's constant.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Planck%27s%20constant. Accessed 31 Mar. 2023.

Medical Definition

Planck's constant

noun
: a constant that gives the unvarying ratio of the energy of a quantum of radiation to its frequency and that has an approximate value of 6.626 × 10−34 joule second
symbol h
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