casualty

noun

ca·​su·​al·​ty ˈka-zhəl-tē 

ˈkazh-wəl-, 

ˈka-zhə-wəl- 

plural casualties

1

a

: a military person lost through death, wounds, injury, sickness, internment, or capture or through being missing in action

The army sustained heavy casualties.

b

: a person or thing injured, lost, or destroyed : victim

The ex-senator was a casualty of the last election.

2

: serious or fatal accident : disaster

Losses from fire, storm, or other casualty …

—J. S. Seidman

3

archaic : chance, fortune

… losses that befall them by mere casualty …

—Sir Walter Raleigh

Synonyms of casualty

• victim
• fatality

Examples of casualty in a Sentence

a low number of casualties

the real casualties in the war against drugs are millions of innocent children

Recent Examples on the Web

The administration confronts anger over rising costs, reclassified casualties and Brent crude near $95 a barrel, with gas prices and inflation squeezing Americans as Republicans try to protect narrow congressional majorities. — Aamer Madhani, Los Angeles Times, 4 Sep. 2026

Clashes stopped in the early afternoon, but there was no official information on casualties or the extent of the fighting. — ABC News, 3 Sep. 2026

In its war against Ukraine, Russia has also demonstrated a high tolerance for military casualties. — Francesca Chambers, USA Today, 2 Sep. 2026

Manufacturers of untested products are most likely to get caught only when there’s a customer casualty count. — Alison J. Stein, HubSpot, 1 Sep. 2026

Word History

Etymology

see casual entry 1

First Known Use

15th century, in the meaning defined at sense 3

Kids Definition

casualty

noun

ca·​su·​al·​ty ˈkazh-əl-tē 

ˈkazh-(ə-)wəl-

plural casualties

1

: a serious or fatal accident : disaster

2

a

: a military person lost (as by death or capture) during warfare

b

: a person or thing injured, lost, or destroyed

Medical Definition

casualty

noun

ca·​su·​al·​ty ˈkazh-əl-tē, ˈkazh-(ə-)wəl- 

plural casualties

1

: a serious or fatal accident

2

: a military person lost through death, wounds, injury, sickness, internment, or capture or through being missing in action

3

a

: injury or death from accident

b

: one injured or killed (as by accident)

Legal Definition

casualty

noun

ca·​su·​al·​ty ˈka-zhəl-tē, ˈka-zhə-wəl- 

plural casualties

1

: an unfortunate occurrence

especially : a serious and often disastrous accident

conversion of property…arising from fire, storm, shipwreck, or other casualty

—Internal Revenue Code

2

: something lost, stolen, damaged, or destroyed see also casualty gain at gain, casualty loss at loss