A depiction of a Roman decimation. William Hogarth/Wikipedia Commons
If you’ve been following the news, you might have noticed President Trump using the word “decimate” frequently to describe U.S. military action against Iran. In an April 1 address about Operation Epic Fury he said, “We’ve beaten and completely decimated Iran. They are decimated both militarily and economically.”
Today many people use “decimate” to mean “destroy” or “devastate.” Fewer realize the word’s origins and how its meaning has shifted over time. Michiel de Vaan, an etymologist at the University of Basel, traces decimate to Latin decimatio, from decimus, meaning “tenth.” In its original use decimatio referred specifically to killing one-tenth of a group of soldiers as punishment.
A decimation was a brutal, precise form of discipline in the Roman army, deployed rarely but with severe consequences. As historian Gregory Aldrete explains, the punished unit would draw lots and every tenth man was clubbed to death by nine comrades. The idea was to shock the survivors into obedience while limiting overall manpower loss.
The Roman historians Plutarch and Appian record a famous example from 72 B.C. during the Third Servile War. When a unit fled from battle against Spartacus’s slave army, General Marcus Licinius Crassus ordered a decimation. Scholars have debated Crassus’s motives; Barry Strauss of the Hoover Institution suggests that facing a serious insurrection, Crassus may have believed a dramatic punishment was needed to restore discipline and that, as an ambitious politician, he judged he could get away with it.
How did a word meaning “kill one-tenth” come to mean “destroy”? De Vaan notes a parallel use in biblical translations, where taking a tenth referred to tithing. Between the end of the Roman Empire and the Renaissance the word largely fell out of use, then was revived by classical scholars. Over time its sense shifted—first to “leave only one tenth,” and by the mid-17th century to a general sense of devastation.
That semantic drift has long annoyed language purists. Richard Grant White in 1870 criticized Civil War correspondents who used “decimate” to mean wholesale slaughter. Lake Superior State University put “decimate” on its 2008 list of banished words, reflecting continued complaints about misuse.
But many editors and linguists point out that meanings change. NPR copy editor Preeti Aroon recalls defending the word when a reader objected to its use; she told an editor, “Meanings change over time.” Language evolves as generations pass, and usage that once seemed wrong can become standard.