dec ‧ i ‧ mate /ˈdesəmeɪt, ˈdesɪmeɪt/ BrE AmE verb [transitive]
[ Date: 1500-1600 ; Language: Latin ; Origin: decimatus , past participle of decimare 'to remove one tenth, kill one in ten' , from decem 'ten' ]
to destroy a large part of something:
The population has been decimated by disease.
—decimation /ˌdesəˈmeɪʃ ə n, ˌdesɪˈmeɪʃ ə n/ noun [uncountable]