tr.v. dec·i·mat·ed, dec·i·mat·ing, dec·i·mates
1. To destroy or kill a large part of (a group of people or organisms).
2. Usage Problem
a. To inflict great destruction or damage on: The storm decimated the region.
b. To reduce markedly in amount: a profligate heir who decimated his trust fund.
3. To select by lot and kill one in every ten of (a group of soldiers).
[Latin decimāre, decimāt-, to punish every tenth person, from decimus, tenth, from decem, ten; see dek in the Appendix of Indo-European roots.]
Usage Note: Decimate originally referred to the killing of every tenth person, a punishment used in the Roman army for mutinous legions. Today this meaning is commonly extended to include the killing of any large proportion of a population. In our 2005 survey, 81 percent of the Usage Panel accepts this extension in the sentence The Jewish population of Germany was decimated by the war, even though it is common knowledge that the number of Jews killed was much greater than a tenth of the original population. This is an increase from the 66 percent who accepted this sentence in our 1988 survey. However, the Panel is less accepting of usages that extend the meaning to include large-scale destruction other than killing, as in The supply of fresh produce was decimated by the nuclear accident at Chernobyl. Some 36 percent accepted this sentence in 2005, up from 26 percent in 1988, but still a decided minority.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.