decimation

UK: /ˌdɛsɪˈmeɪʃ^ən/ US: /ˌdɛsəˈmeɪʃən/

WordReference Random House Learner's Dictionary of American English © 2025

dec•i•mate /ˈdɛsəˌmeɪt/   v. [ ~ + obj], -mat•ed, -mat•ing. 

1. to destroy a great number or part of:
   Cholera decimated the population.
2. (esp. in ancient Rome) to select by lot and kill every tenth person of.

dec•i•ma•tion /ˌdɛsəˈmeɪʃən/  n. [uncountable] See -dec-.

WordReference Random House Unabridged Dictionary of American English © 2025

dec•i•mate  (des′ə māt′), v.t., -mat•ed, -mat•ing. 

1. to destroy a great number or proportion of:
   The population was decimated by a plague.
2. to select by lot and kill every tenth person of.
3. [Obs.] to take a tenth of or from.

• Latin decimātus, past participle of decimāre to punish every tenth man chosen by lot, verb, verbal derivative of decimus tenth, derivative of decem ten; see ate¹
• 1590–1600

dec′i•ma′tion, n. 
dec′i•ma′tor, n. 
Usage

The earliest English sense of decimate is "to select by lot and execute every tenth soldier of (a unit).'' The extended sense "destroy a great number or proportion of '' developed in the 19th century:
Cholera decimated the urban population.
Because the etymological sense of one-tenth remains to some extent, decimate is not ordinarily used with exact fractions or percentages:
Drought has destroyed (not decimated) nearly 80 percent of the cattle.