Decimate once had a very specific meaning. In ancient Rome, it referred to a punishment in which one in ten soldiers in a group were killed. That is the historical source of the word.
In modern English, though, decimate usually means to destroy, ruin, or reduce a large part of something. Most writers and dictionaries now accept this broader meaning as standard.
For example, you might read:
- The storm decimated the citrus crop. Here, the meaning is severe destruction, not a precise loss of ten percent.
- Injuries decimated the team. This means the team lost many players, not exactly one in ten.
Some people still prefer the older, literal sense and object when decimate is used more loosely. That preference reflects the word’s history, but it does not match how the word is most often used today.
A helpful way to remember it is this: the original meaning was exact, but the current common meaning is general and much broader.