Source: Primary reference
Khapwa is a Persian name for an Indian dagger resembling what collectors now mainly refer to as the chilanum.
The Ain-i-Akbari (Persian: آئینِ اکبری) or the "Administration of Akbar" of the 16th-century depicts three sheathed daggers with a chilanum-like shape which are called khapwa, jhanbwah and bank. The khapwa in the illustration doesn't have the characteristic ball grip often seen on chilanum.
Judging from the scabbards, the blades on the depicted daggers have a single curve in them, they do not seem to recurve as most chilanum seem to do.
(Jhanbwah is probably an alternative spelling of Jambiya, an Arabic name for a dagger.)
Daggers in the Ain-I-Akbari.
1. Jamdhar, "deadly edge". In this case a curved katar is illustrated but the name was used for all types.
2. Jamdhar doulicaneh, "two-pointed deadly edge". A katar with two blades.
3. Jamdhar sehlicaneh, "three-pointed deadly edge". A katar with three blades.
4. Khapwah, a dagger of a type now mostly know as chilanum.
6. Katarah, similar to the Jamdhar kátári
8. Narsingmot'h, a type of dagger used by Narsinga, an incarnation of Vishnu. The looped hilt resembles that of the bichuwa (बिछुवा) dagger.
9. Gupti kard, literally "long knife". Notice the edge is on the inside curve.
1. Ain-i-Akbari (آئینِ اکبری) or the "Administration of Akbar" describing the court of Akbar as it was around 1590.
2. Manouchehr Moshtagh Khorasani; Lexicon of Arms and Armor from Iran. Legat Verlag GmbH, Tübingen, 2010. Page 186.