I refer readers to an excellent description of this weapon at Atkinsons swords on http://atkinson-swords.com/collecti...fghanistan.html
and by the author above at # 10.
I extract from his fine summary the following; Quote"There is much debate about the origin of the name and in fact which name is “correct” (jamadhar, jandad, jamdhar, jumdud). The spelling jamdhar seems to indicate Hindi origin yet “Jamdar” may also be a Persian word with the suggested etymology of janb-dar, that is, 'flank render.' An alternative theory is that "jamdhar" is an evolution of the words "Yama" (Lord of death to Hindus) and "Daushtra" (tooth, in Sanskrit). This became "Yama+Dadh", Jamdhad, and now "Jamdhar". In support of this derivation, the word "katar" was originally termed "jamdhar" and loosely translated as "tooth of death." The term "katar" is now applied generally to transverse grip "push" daggers".Unquote.