Etymograph

English

acidity

Acidity comes from Latin aciditās ‘sourness, acidity’, from acidus ‘sour, acid’, and ultimately from Proto-Indo-European *h₂eḱ- ‘sharp’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂eḱ-1‘sharp’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*h₂eḱéh₁yeti1reconstructed
  3. Proto-Italicc. 1500–700 BCE*akēō1reconstructed
  4. Latinc. 75 BCE–200 CEaceō1‘to be sour’
  5. Latinc. 75 BCE–200 CEacidus2‘sour, acid’
  6. Latinc. 75 BCE–200 CEaciditās2‘sourness, acidity’
  7. Latinc. 75 BCE–200 CEaciditātem2accusative singular of aciditās
  8. Frenchc. 1600–presentacidité2
  9. Englishearliest quotation 1912acidity2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin acidus
  2. 2 Wiktionary, English acidity
  3. Earliest quotation in Wiktionary’s entry: 1912, Arthur Conan Doyle, The Lost World […]: “"What shall we call it?" he asked. "Why should…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂eḱ-Wiktionary, Latin acidus‘sharp’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*h₂eḱéh₁yetiWiktionary, Latin acidusreconstructed
  3. Proto-Italicc. 1500–700 BCE*akēōWiktionary, Latin acidusreconstructed
  4. Latinc. 75 BCE–200 CEaceōWiktionary, Latin acidus‘to be sour’
  5. Latinc. 75 BCE–200 CEacidusWiktionary, English acidity‘sour, acid’
  6. Latinc. 75 BCE–200 CEaciditāsWiktionary, English acidity‘sourness, acidity’
  7. Latinc. 75 BCE–200 CEaciditātemWiktionary, English acidityaccusative singular of aciditās
  8. Frenchc. 1600–presentaciditéWiktionary, English acidity
  9. Englishearliest quotation 1912acidityWiktionary, English acidity. Earliest quotation in Wiktionary’s entry: 1912, Arthur Conan Doyle, The Lost World […]: “"What shall we call it?" he asked. "Why should…”

Linked words

through Proto-Indo-European *h₂eḱ- ‘sharp’

hear, edge, egg, ear, hammer, eager, axe, acute, vinegar, oxide, acne, mediocre, paragon, acupuncture, hark, exacerbate, acumen, mediocrity, acme, acacia, rosacea, acuity, acrimony, exacerbation, acerbic, acrid, 72 more

through Latin aceō ‘to be sour’

acetate, acyl, 23 more

through Latin acidus ‘sour, acid’

roselle, 8 more

Today it means

noun The quality or state of being acid.

Sources

Sources: Wiktionary, “acidity”; the older steps come from the Wiktionary entry for Latin acidus. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.

Etymograph / Proto-Indo-European *h₂eḱ- / acidity

Shirt and support for this word