Etymograph

English

reason

Reason comes from Latin ratiō ‘reason, reasoning, explanation, ground,…’, from ratus ‘considered, having considered’, and ultimately from Proto-Indo-European *h₂er- ‘to put together’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂er-1‘to put together’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*h₂reh₁-1‘to think’reconstructedreanalysed root of *h₂er-
  3. Latinc. 75 BCE–200 CEreor1‘reckon’
  4. Latinc. 75 BCE–200 CEratus1‘considered’past participle of reor
  5. Latinc. 75 BCE–200 CEratiō1‘reason’
  6. Anglo-Normanc. 1066–1400raisun1
  7. Middle Englishc. 1150–1500resoun1
  8. Englishearliest quotation 1734reason1

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, English reason
  2. Earliest quotation in Wiktionary’s entry: 1734, Isaac Barrow, London: […] Stephen Austen: “[I]f two Quantities repreſented by the Numbers 20 and…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₂er-Wiktionary, English reason‘to put together’reconstructed
  2. Proto-Indo-Europeanc. 4500–2500 BCE*h₂reh₁-Wiktionary, English reason‘to think’reconstructedreanalysed root of *h₂er-
  3. Latinc. 75 BCE–200 CEreorWiktionary, English reason‘reckon’
  4. Latinc. 75 BCE–200 CEratusWiktionary, English reason‘considered’past participle of reor
  5. Latinc. 75 BCE–200 CEratiōWiktionary, English reason‘reason’
  6. Anglo-Normanc. 1066–1400raisunWiktionary, English reason
  7. Middle Englishc. 1150–1500resounWiktionary, English reason
  8. Englishearliest quotation 1734reasonWiktionary, English reason. Earliest quotation in Wiktionary’s entry: 1734, Isaac Barrow, London: […] Stephen Austen: “[I]f two Quantities repreſented by the Numbers 20 and…”

Word family

English words that share an ancestor with reason, grouped by the ancestor they share, most familiar first.

through Proto-Indo-European *h₂er- ‘to put together’

  • order ← ordre ← ordne ← ōrdinem ← *ordō
  • art ← artem ← ars ← *artis ← *h₂értis
  • article ← articulus ← artus ← *h₂értus
  • army ← armee ← armee ← armātus ← armō
  • artist ← artiste ← artista ← ars ← *artis
  • ready ← redy
  • arm ← earm ← *armaz ← *h₂érmos
  • ordinary ← ordenarie ← ordinaire ← ordinarius ← ōrdō
  • alarm ← alarme ← alarme
  • armor ← armure ← armure ← armeure ← armātūra
  • harmony ← armonye ← harmonie ← harmonia ← ἁρμονία
  • coordinate ← coōrdinātus ← ōrdinō ← ōrdō ← *ordō

139 more relatives in the full family tree

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Another origin of reason

  1. Proto-Indo-Europeanc. 4500–2500 BCE*h₁erh₁-‘to rest’uncertain
  2. Proto-Germanicc. 500 BCE–200 CE*razną‘house, dwelling’uncertain
  3. Proto-West Germanicc. 200–500 CE*raʀn‘house’uncertain
  4. Old Englishc. 450–1150ræsn‘beam, rafter, ceiling, wall panel’
  5. Middle Englishc. 1150–1500reason
  6. Englishtodayreason

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Today it means

noun A cause: That which causes something: an efficient cause, a proximate cause.

Sources

Sources: Wiktionary, “reason”. 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 *h₂er- / reason