If you’ve followed recent news, you may have noticed President Trump frequently using the word “decimate” 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.”
Most people today take “decimate” to mean “destroy” or “devastate,” but the word’s origin and original meaning are much more specific. Etymologist Michiel de Vaan of the University of Basel traces it to Latin decimatio, from decimus, meaning “tenth.” In ancient Rome, decimatio referred to killing one-tenth of a group of soldiers as a form of discipline — a precise, brutal punishment rather than a vague notion of wholesale destruction.
A decimation was imposed when an entire unit was judged collectively guilty of failures such as cowardice. As Gregory Aldrete, professor emeritus of history, explains, the condemned unit would draw lots and every tenth man was clubbed to death by the other nine. The logic was pragmatic: sacrificing 10% would shock and discipline the survivors while preserving most of the unit’s fighting strength.
Roman historians Plutarch and Appian record a famous instance in 72 B.C. during the Third Servile War. Marcus Licinius Crassus, fighting Spartacus’s slave rebellion, reportedly ordered a decimation after a unit fled the field. Scholars have debated Crassus’s motives; Barry Strauss of the Hoover Institution suggests the severe punishment was intended to shock the army back into discipline and that Crassus — an ambitious politician — judged he could impose it without unacceptable political cost.
The word’s journey from this narrow military sense to its modern general use involved shifts in meaning over centuries. De Vaan notes that while decimatio referred to taking a tenth, a related sense appeared in biblical translations referring to tithing — giving one-tenth. After falling out of common use between the end of the Roman Empire and the Renaissance, classical scholars revived the term, and its meaning began to flip: it came to mean “to leave only one tenth” and then more broadly “to destroy.” By the mid-17th century, decimate was being used to mean “devastate.”
That semantic broadening has long annoyed language purists. In 1870, Richard Grant White criticized uses equating decimate with wholesale slaughter as “simply ridiculous.” Lake Superior State University put “decimate” on its 2008 list of banished words, reflecting continuing complaints about perceived misuse. But editors and linguists counter that meanings change. NPR copy editor Preeti Aroon recounts defending contemporary usage at Foreign Policy, arguing that language evolves and younger generations’ usages typically prevail as older speakers pass on.
In short, “decimate” began as a very specific Roman disciplinary measure — killing one-tenth — and over centuries shifted through biblical and scholarly contexts into a general synonym for severe destruction. That evolution explains both why some recoil at its modern use and why most readers today accept it to mean “devastate.”