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

Relatives of the casualties could be seen weeping outside a local hospital. —Esha Mitra, CNN Money, 10 Nov. 2025

Emergency responders transported the injured to LNJP Hospital while authorities cleared the area to prevent further casualties. —Amir Daftari, MSNBC Newsweek, 10 Nov. 2025

Former Premier League players Nemanja Matic, who is from Vrelo in Serbia, and James McClean, born in Derry (officially Londonderry) in Northern Ireland, both decided against wearing the poppy on matchdays due to conflicts their communities had with British units that resulted in casualties. —Eduardo Tansley, New York Times, 8 Nov. 2025

Britain ultimately lost not only because of Washington’s extraordinary tenacity in the war’s several mainland theaters, but also because the king’s men had to stage long sieges, wage desperate naval battles, and take mounting casualties on too many other fronts spread too far apart. —Literary Hub, 7 Nov. 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