From Hindi बन्दूक (bandūk, “gun”), from Arabic بُنْدُقِيَّة (bunduqiyya, “rifle, gun”). The original Arabic was بُنْدُق (bunduq) and denoted filberts, nuts shaped like the projectiles thrown from stone bows. That usage was eventually transferred to the bows themselves and eventually to firearms.
bundook (plural bundooks)
A term widely adopted by British regular soldiers serving in India or having contact with Indian troops.