Etymograph

English

pepsin

Pepsin comes from Ancient Greek πέψις ‘digestion’, from πέσσω ‘to ripen’, and ultimately from Proto-Indo-European *pekʷ- ‘to crack, crush (foodstuff), pulverize (grain)’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*pekʷ-1‘to crack, crush (foodstuff), pulverize (grain)’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*pékʷ-ye-1reconstructed
  3. Ancient Greekc. 800–300 BCEπέσσω2‘to ripen’
  4. Ancient Greekc. 800–300 BCEπέψις3pépsis‘digestion’
  5. Germanc. 1650–presentPepsin3
  6. Englishtodaypepsin3

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Ancient Greek πέσσω
  2. 2 Wiktionary, Ancient Greek πέψις
  3. 3 Wiktionary, English pepsin

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*pekʷ-Wiktionary, Ancient Greek πέσσω‘to crack, crush (foodstuff), pulverize (grain)’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*pékʷ-ye-Wiktionary, Ancient Greek πέσσωreconstructed
  3. Ancient Greekc. 800–300 BCEπέσσωWiktionary, Ancient Greek πέψις‘to ripen’
  4. Ancient Greekc. 800–300 BCEπέψιςWiktionary, English pepsinpépsis‘digestion’
  5. Germanc. 1650–presentPepsinWiktionary, English pepsin
  6. EnglishtodaypepsinWiktionary, English pepsin

Formed from in

Proto-Indo-European *h₁én ‘in’

Proto-Germanic *in

Proto-West Germanic *in

Old English in

Middle English in ‘inside’

English in

Linked words

through Proto-Indo-European *pekʷ- ‘to crack, crush (foodstuff), pulverize (grain)’

coach, cook, kitchen, pumpkin, cuisine, culinary, kiln, concoction, ricotta, quitter, concoct, decoction, 13 more

through Ancient Greek πέσσω ‘to ripen’

peptide, 6 more

through Ancient Greek πέψις ‘digestion’

peptic, dyspepsia, 1 more

Today it means

noun A digestive enzyme that chemically digests, or breaks down, proteins into shorter chains of amino acids.

Sources

Sources: Wiktionary, “pepsin”; the older steps come from the Wiktionary entries for Ancient Greek πέσσω, Ancient Greek πέψις. 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 *pekʷ- / pepsin

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