Etymograph

English

certain

Certain comes from Old French certain, from Vulgar Latin *certānus, from Latin certus ‘fixed, certain’, ultimately from Proto-Indo-European *krey- ‘to sift’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*krey-1‘to sift, separate’reconstructed
  2. Proto-Italicc. 1500–700 BCE*kritos1reconstructed
  3. Latinc. 75 BCE–200 CEcertus2‘fixed, resolved, certain’
  4. Vulgar Latinc. 100–700 CE*certānus3reconstructed
  5. Old Frenchc. 842–1400certain2‘certain’
  6. Middle Englishc. 1150–1500certeyn2‘specified, fixed’
  7. Englishearliest quotation c. 1596–1599certain2

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin certus
  2. 2 Wiktionary, English certain
  3. 3 Wiktionary, Old French certain
  4. Earliest quotation in Wiktionary’s entry: c. 1596–1599, William Shakespeare, The Second Part of Henrie the Fourth: “[…]death (as the Pſalmiſt ſaith) is certaine to all,…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*krey-Wiktionary, Latin certus‘to sift, separate’reconstructed
  2. Proto-Italicc. 1500–700 BCE*kritosWiktionary, Latin certusreconstructed
  3. Latinc. 75 BCE–200 CEcertusWiktionary, English certain‘fixed, resolved, certain’
  4. Vulgar Latinc. 100–700 CE*certānusWiktionary, Old French certainreconstructed
  5. Old Frenchc. 842–1400certainWiktionary, English certain‘certain’
  6. Middle Englishc. 1150–1500certeynWiktionary, English certain‘specified, fixed’
  7. Englishearliest quotation c. 1596–1599certainWiktionary, English certain. Earliest quotation in Wiktionary’s entry: c. 1596–1599, William Shakespeare, The Second Part of Henrie the Fourth: “[…]death (as the Pſalmiſt ſaith) is certaine to all,…”

Linked words

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

secret, crime, crisis, criminal, discrimination, critic, discretion, critique, discrete, riddle, discreet, hypocrite, discriminate, criterion, endocrine, discern, excrement, excretion, rime, incriminate, excrete, incrimination, recrimination, ridder, criterium, 46 more

through Latin certus ‘fixed, resolved, certain’

certitude, 7 more

Today it means

adj Sure in one's mind, positive; absolutely confident in the truth of something.

Sources

Sources: Wiktionary, “certain”; the older steps come from the Wiktionary entries for Latin certus, Old French certain. 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- / certain

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