Now meaning to destroy or wipe out a great number, it;s from the Latin word for "ten"
I always 
flinch when I hear someone use the word decimate to mean "wipe out," as in, "
The... [DOC] [TLE] Decimate | Definition of Decimate by Merriam-Webster [PAR] Define decimate: to destroy a large number of (plants, animals, people, etc.)