['d?s?me?t]
¦ verb
1. kill or destroy a large proportion of.
drastically reduce the strength of.
2. (in ancient Rome) kill one in every ten of (a group of soldiers) as a punishment for the mutiny of the whole group.
Derivatives
decimation noun
decimator noun
Origin
ME: from L. decimat-, decimare 'take as a tenth', from decimus 'tenth'.
Usage
The earliest sense of decimate, 'kill one in every ten of', has been more or less totally superseded by the more general sense 'kill or destroy (a large proportion of)'. Some traditionalists argue that this later sense is incorrect, but it is clear that this is now part of standard English.