You have inverted it.
Decimate literally means killing 9 out of 10 or cutting the opposing force down to 1/10 of the size.
But in general it is a euphamism any route but especially any route where the force is destruyed to ranks level and requires a total rebuild.
I don't think so. The dictionary says:
"to select by lot and kill every tenth one of"
This is in agreement with ops33's post #25.
Uh, I don’t think so.
Webster says:
Main Entry: dec·i·mate
Pronunciation: ‘de-s&-”mAt
Function: transitive verb
Inflected Form(s): -mat·ed; -mat·ing
Etymology: Latin decimatus, past participle of decimare, from decimus tenth, from decem ten
1 : to select by lot and kill every tenth man of