Phrase guide

Planck length

noun · 1 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

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Pronunciation

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1

noun

Meaning 1

A unit of length, believed to be the scale at which quantum gravity effects become significant, that is defined in terms of the speed of light, the gravitational constant and the reduced Planck's constant, namely: l_P=√hbar Gc3≈1.616 252(81)×10−35 mbox m

Definition source: English Wiktionary via Wiktextract

Topics: natural-sciences, physical-sciences, physics

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

Named after Max Planck, who defined it.

Across languages

Translations

4 source translations are retained for this English entry.

  • French: longueur de Planck — unit of length, believed to be the scale at which quantum gravity effects become significant
  • Japanese: プランク長 (puranku chō) — unit of length, believed to be the scale at which quantum gravity effects become significant
  • Korean: 플랑크 길이 (peullangkeu giri) — unit of length, believed to be the scale at which quantum gravity effects become significant
  • Polish: długość Plancka — unit of length, believed to be the scale at which quantum gravity effects become significant