Today we have a request from a reader to clarify the definitions of "regime" and "regimen."
REGIME: a regular occurrence of a pattern or action; a mode of rule or management; a form of government or administration--specifically, a governmental or social system.
REGIMEN: a systematic course of therapy; the characteristic behavior or orderly procedure of a natural phenomenon or process.
You can see, therefore, why reference to a "diet regime" makes one think of a national diet...probably not a bad idea in this day of mass obesity, but ungrammatical. A "diet regimen," on the other hand, is therapeutic dieting.
Here's another one I encountered in my own reading and this was especially interesting: gristly versus grizzly.
GRISTLY: composed of cartilage
GRIZZLY: sprinkled, streaked or mixed with gray
The interesting thing here is that an author and editor had used grizzly. Someone took them to task, explaining that the proper word was gristly. She should have done what she criticized them for not doing and looked it up. The context in which the word was used was in the description of a murder scene. Therefore, all three people were wrong because the correct word is "grisly," meaning horrible or gruesome.
We all live and learn.