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 piece highlights the challenges of documenting casualties amid ongoing conflict and restricted access for journalists. —Hilary Lewis, HollywoodReporter, 9 Apr. 2026

Hezbollah retaliated to the heavy strikes — which prompted an international outcry — by launching missiles into Israel, though no serious casualties have been reported. —Abby Sewell, Chicago Tribune, 9 Apr. 2026

The first casualty will likely be our planned Downtown Civic Campus redevelopment. —John Gates, Denver Post, 9 Apr. 2026

According to the Reuters news service, Lebanon's civil defense service said the new strikes had killed more than 250 people — heaping more casualties on the more than 1,500 in Lebanon already killed in the more than five-week-old Israeli invasion. —Matt Bradley, NBC news, 8 Apr. 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