acid (English)

Where does "acid" come from?

The English word 'acid' traces back to the Proto-Indo-European root *h₂eḱ-, meaning 'sharp.' This evolved into the Latin verb 'aceō,' meaning 'I am sour,' which eventually gave rise to the Latin adjective 'acidus.' After passing through Middle French as 'acide,' the term entered the English language, where it transitioned from describing a simple sour taste to covering a range of scientific, chemical, and, eventually, slang meanings.

Full etymology tree

• acid (English), 'A sour substance.'
  • borrowed acide (French), 'acid, acidic, sour, tart'
    • borrowed acidus (Latin), 'sour, tart, acid, bitter'
      • derived aceō (Latin), 'to be sour'
        • inherited *h₂éḱ-eh₁ye-ti (Proto-Indo-European)
          • derived *h₂eḱ- (Proto-Indo-European), 'sharp'
      • affix -idus (Latin), 'tending to'

Direct ancestors

• h₂eḱ- (Proto-Indo-European)
• acide (French)
• acidus (Latin)
• agita (English)
• acetic (English)

Updated July 2026

Etymology data from Wiktionary, CC BY-SA 4.0 · About Miraris