I agree with Ariel and (it seems) everyone else that this discussion is a bit silly. Whether we like it or not, in modern times, katar is staying as the "common" name for these punch daggers until a tv show or movie calls it a jam(a)dhar.
I also personally prefer the name jamdhar, partially because the (incorrect?) explanation that it means "tooth of death" sounds really cool to me, but also because when I say "katar" out loud it sounds a bit too close to "guitar" for comfort, so jamdhar is easier for me to say
Actually on that note, though, Mercenary, as you seem rather knowledgeable in Hindi/Sanskrit, is the idea that jama = yama, the god of death, totally false? It's just that, personally, I could totally see yama becoming jama, and, with the edition of dhar, the word overall translating to some version of tooth/blade of death.
Finally, just to continue our discussion of odd katar forms, I've attached some examples that always looked unusual to me (and are hopefully discussion-provoking to you guys). The last one isn't technically a katar, but these odd "parrying weapons" seem to always be mounted with katar blades.