From today's New York Times:
Since 1997, bird flocks in 11 countries have been decimated by flu outbreaks. So far nearly all the people infected Â? more than 100, including more than 60 who died Â? contracted the sickness directly from birds. However, there has been little transmission between people.
The word "decimate" means something quite specific: to reduce the enemy's army by 1/10th. The Romans killed one out of ten soldiers in order to teach a lesson.
Think about it: "decimate". As in "decade" or "decimal" -- involving digits, or parts of 10.
Licentious dictionaries accept as a third meaning "to reduce drastically especially in number".
Thus even Governor Blanco of Louisiana gets that meaning wrong. She claims in her speeches that Katrina "decimated" New Orleans. Katrina wrought havoc on the city, and caused tremendous damage. But, thankfully, Katrina did not cause the huge loss of life the mayor and others predicted. Not even close to one in ten.
Katrina did not decimate New Orleans, and the 1918 flu pandemic, however horrible, did not kill 10% of any population.