Etymograph

English

ascertain

Ascertain comes from Old French acertener ‘to assure’, from Latin certus ‘certain, fixed’, and ultimately from Proto-Indo-European *krey- ‘to sift, separate, divide’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*krey-1‘to sift, separate, divide’reconstructed
  2. Proto-Italicc. 1500–700 BCE*kritos1reconstructed
  3. Latinc. 75 BCE–200 CEcertus2‘certain, fixed’
  4. Old Frenchc. 842–1400acertener2‘to assure’
  5. Middle Englishc. 1150–1500acerteynen2
  6. Englishearliest quotation 1436ascertain2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin certus
  2. 2 Wiktionary, English ascertain
  3. Earliest quotation in Wiktionary’s entry: 1436, Sir Nicholas Harris Nicolas, Proceedings and Ordinances of the Privy Council of England: “Therfore the saide cõmissioners shall mowe say that nowe…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*krey-Wiktionary, Latin certus‘to sift, separate, divide’reconstructed
  2. Proto-Italicc. 1500–700 BCE*kritosWiktionary, Latin certusreconstructed
  3. Latinc. 75 BCE–200 CEcertusWiktionary, English ascertain‘certain, fixed’
  4. Old Frenchc. 842–1400acertenerWiktionary, English ascertain‘to assure’
  5. Middle Englishc. 1150–1500acerteynenWiktionary, English ascertain
  6. Englishearliest quotation 1436ascertainWiktionary, English ascertain. Earliest quotation in Wiktionary’s entry: 1436, Sir Nicholas Harris Nicolas, Proceedings and Ordinances of the Privy Council of England: “Therfore the saide cõmissioners shall mowe say that nowe…”

Linked words

through Proto-Indo-European *krey- ‘to sift, separate, divide’

secret, crime, crisis, criminal, discrimination, critic, critique, discretion, riddle, discrete, hypocrite, criterion, discreet, discriminate, endocrine, excrement, discern, excretion, rime, incriminate, excrete, incrimination, recrimination, ridder, criterium, 44 more

through Latin certus ‘certain, fixed’

certainly, certainty, certitude, 5 more

Today it means

verb To find out definitely; to discover or establish.

Sources

Sources: Wiktionary, “ascertain”; the older steps come from the Wiktionary entry for Latin certus. 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 *krey- / ascertain

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