Decimate can mean both “to destroy a large number of (plants, animals, people, etc.)” or “to severely damage or destroy a large part of (something).”
In ancient Rome it
had a very singular meaning: “to select by lot and kill every tenth man of a
military unit.” However, many words in English descended from Latin have
changed and/or expanded their meanings in their travels. For example, we no
longer think of sinister as meaning “on the left side,” and delicious can
describe things both tasty and delightful. Was the “to kill every tenth man”
meaning the original use of decimate in English? Yes, but not by much. It took
only a few decades for decimate to acquire its broader, familiar meaning of “to
severely damage or destroy,” which has been employed steadily since the 17th
century.
