Your chillanum is from the 17th c.

[Jim McDougall]

Originally Posted by Mercenary

because the miniature school itself appears in India in the second half of the 16th century

Good point Mercenary, I had not realized that this particular convention in art had not begun in India until then. So feasibly the dagger form may have existed earlier in degree.
You have noted a variation in term khapwa and chilanum. Where exactly do these terms come from? and are they terms actually in local dialects or contrived as we have seen in some other terms for weapon forms?