[NoBlackHats]

They are by me. I think "cosy" really just refers to the tone of the books. The more grit and authenticity, the less cosy it is. Poirot mysteries are not in any way gory or disturbing, but are character-based rather than procedure-based. That, to me, makes them cosy.

I'd agree with that. There are definitely different flavors of cozies as the genre has developed, including paranormal and some with stronger language or grittier bad guys, but to me, it's all about the interesting characters.