Etymology

femtojoule

F4E1M3T1O1J8O1U1L1E1

Today it means: An SI unit of energy, work, and heat equal to 10⁻¹⁵ joules. Symbol: fJ Full definition →

English joule ← Danish femten ← Old Norse fimmtán
Ask AI about its historyChatGPTClaudePerplexityGoogle AIGrok

The story

  1. Proto-Indo-European*pénkʷe
  2. Proto-Germanic*fimf
  3. Proto-Indo-European*déḱm̥
  4. Proto-Germanic*tehun
  5. Proto-Germanic*fimftehun
  6. Old Norsefimmtán
  7. Danishfemten
  8. Englishfemto-
  9. Englishjoule
  10. English todayfemtojoule

From femto- + joule.

Etymology from Wiktionary, CC BY-SA 4.0.