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

In his second season, Dallas Cowboys wide receiver Ryan Flournoy has gone from a preseason roster casualty to firmly cementing himself as the third receiver option behind CeeDee Lamb and George Pickens. —Nick Harris, Fort Worth Star-Telegram, 23 Dec. 2025

Evacuating casualties by air has never been a good option for Ukraine, as Russia has had control over much of the country’s airspace since the early days of the war. —Ivana Kottasová, CNN Money, 21 Dec. 2025

There is a low likelihood of casualties and damage. —Ca Earthquake Bot, Sacbee.com, 21 Dec. 2025

There were no casualties during the 2014 mission, which was carried out on orders from former President Barack Obama in international waters southeast of Cyprus at the request of the Libyan and Cypriot governments. —Greg Wehner, FOXNews.com, 21 Dec. 2025

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