I love this! The linguaphile pedant in me seethes every time someone uses the modern definition of decimation and it sometimes takes physical effort not to be THAT guy about it 😅
Nah, I know that the common usage is by definition also correct, but that doesn't mean I have to like it any more than "literally" also meaning "figuratively" now.
Decimation was a practice of group punishment in Roman times, where if a group of 100 soldiers deserted, you might punish them by forcing them to kill 1 in 10 of their rank. 1 in 10 would be beaten to death by the other 9. Nowadays, we use decimate to mean a significant loss in general, but the root Latin "decimatio" literally meant "removal of a tenth".
The Matt Helm spy books of the 1960s-1980s were far superior to the James Bond novels.
In one of them, the bad guys have an imposter on the phone with Helm, impersonating Helm's long time boss. Helm realizes the scam because the phony misuses 'decimate.' That's how 4th grade me learned this.