That is extremely compelling evidence Radu!! Excellent idea about taking this to a Sikh temple, I look forward to hearing more on the symbols used to mark Sikh swords. Unfortunately the research I did a number of years ago, including speaking with the authors of the book "Warrior Saints" which was published in association with The Sikh Foundation, revealed no evidence of specific markings used historically on Sikh blades.
It is very exciting news that you have positively identified this as a Sikh TALWAR from southern India!!

and relieved us of the search for the correct exotic term for this.Yay!
Jim