Originally Posted by bhushan_lawate
My two cents..!!!
Jamdhar -- originated from the Sanskrit word "Yama Daunstra" literally meeting tooth of Yama -- God of Death
Katar -- is a distorted form of "Kattarak" in Sanskrit -- which means a weapon carried on waist belts. This was used as a dress dagger in the Indian peninsula for a long time similar to the likes of Chillanum or Pesh Kabz.
I can't find anything at the moment to show how these words distorted and came into vogue.