Etymograph

English

casualty

Casualty comes from Middle French casuel ‘fatal’, from Latin cāsus ‘event’, and ultimately from Proto-Indo-European *ḱh₂d-.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*ḱh₂d-1root named by Wiktionary
  2. Proto-Indo-Europeanc. 4500–2500 BCE*ḱád-e-ti2reconstructed
  3. Proto-Italicc. 1500–700 BCE*kadō3‘to fall, sink’reconstructed
  4. Latinc. 75 BCE–200 CEcadō1as cadere‘to fall’next step skipped: Latin cāssus
  5. Latinc. 75 BCE–200 CEcāsus1‘event’
  6. Medieval Latinc. 600–1500casualitas1
  7. Middle Frenchc. 1400–1600casuel1‘fatal’
  8. Englishearliest quotation 1962casualty1

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, English casualty
  2. 2 Wiktionary, Proto-Italic *kadō
  3. 3 Wiktionary, Latin cado
  4. Earliest quotation in Wiktionary’s entry: 1962, Beyond the Channel: Switzerland: Federal aid for three minor: “Among recent casualties is the S.B.B.'s branch from Nyon…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*ḱh₂d-Wiktionary, English casualtyroot named by Wiktionary
  2. Proto-Indo-Europeanc. 4500–2500 BCE*ḱád-e-tiWiktionary, Proto-Italic *kadōreconstructed
  3. Proto-Italicc. 1500–700 BCE*kadōWiktionary, Latin cado‘to fall, sink’reconstructed
  4. Latinc. 75 BCE–200 CEcadōWiktionary, English casualtyas cadere‘to fall’next step skipped: Latin cāssus
  5. Latinc. 75 BCE–200 CEcāsusWiktionary, English casualty‘event’
  6. Medieval Latinc. 600–1500casualitasWiktionary, English casualty
  7. Middle Frenchc. 1400–1600casuelWiktionary, English casualty‘fatal’
  8. Englishearliest quotation 1962casualtyWiktionary, English casualty. Earliest quotation in Wiktionary’s entry: 1962, Beyond the Channel: Switzerland: Federal aid for three minor: “Among recent casualties is the S.B.B.'s branch from Nyon…”

The story

Originally meaning “a chance event” (compare casual, as in “casual encounter”), it developed a negative meaning as “an unfortunate event”, especially the loss of a person.

Full etymology on Wiktionary

Linked words

through Proto-Indo-European *ḱh₂d-

coincidence, cascade, decadence, coincident, 1 more

through Latin cadō ‘to fall’

chance, accident, incident, cheat, occasion, incidence, decay, coincide, deciduous, cadence, decadent, occidental, recidivism, cadaver, occident, 15 more

through Latin cāsus ‘event’

case, 2 more

Today it means

noun Something that happens by chance, especially an unfortunate event; an accident, a disaster.

Sources

Sources: Wiktionary, “casualty”; the older steps come from the Wiktionary entries for Proto-Italic *kadō, Latin cado. 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 *ḱh₂d- / casualty

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