weapon; hand weapon
Refers to a weapon one carries or wields, often with a nuance of a personal arm. Used in both literal and figurative contexts.
He headed to the battlefield with his weapon in hand.
forte; special skill; weapon one is skilled in using
Archaic original meaning; now rare. Refers to one's strong point or the weapon one is particularly adept with. In modern Japanese, 得意 (とくい) or 十八番 (おはこ) are more common for 'forte'.
A journalist who fights using words as their weapon.
It is said that his weapon of choice was the spear.
In old texts, there are stories of samurai whose forte was scholarship.
Compound of 得 (e, 'to obtain; to master') + 物 (mono, 'thing'). The original meaning was 'thing one has mastered' or 'specialty', which later extended to 'weapon one is skilled with' and then simply 'weapon'.