planck
n. countablen. a name used for very small measurements in physics. It refers to the smallest possible scales of energy, time, and space in the universe.
n. Refers to the fundamental physical constants and scales derived by Max Planck, specifically the Planck constant (h). Often used as a modifier to describe the smallest meaningful units of measurement in quantum mechanics, such as Planck length or Planck time.
Scientists study the universe at the Planck scale.
In quantum physics, the Planck constant relates the energy of a photon to its frequency.
Theoretical physicists often encounter significant mathematical hurdles when attempting to reconcile general relativity with the extreme conditions found at the Planck length.
Borrowed from German Planck.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Usually functions as a proper noun or a modifier in scientific compound terms; when used as a unit of measurement, it is countable.
Last updated May 11, 2026