What's the difference between 兵器 and 武器?
兵 (military)
兵器 (tool for military) = weapons; weaponry

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武 (force)
武器 (tool for force) = weapons; arms

Both 兵器 and 武器 means weapons. The difference is 兵器 is more specifically referring to weapon for warfare, while 武器 is a more general term for all weapons

冷兵器 (cold weapons) that are commonly used by soldiers like 刀、劍、長槍、弓箭 、狼牙棒 (Knife, sword, lance, bow and arrow, mace) can all be called 兵器 or 武器.

現代兵器 (modern weapons) like 衝鋒槍、坦克、導彈 (sub-machine gun, tank, guided missile) are all 兵器/ 武器 too

On the other hand, anything that can be used for attack can be qualified as 武器. For example, 剪刀、石塊、摺椅、菜刀 (scissors, stones, folding chairs, kitchen knives) can all be 武器, but no one would call them 兵器 because those items were not commonly used in war


The term 武器 can be used metaphorically, for example: 用言語作为武器 (use words as weapon), but we don't use 兵器 this way
Something that can be called 兵器 can also be called 武器; something that can be used as 武器 but isn't commonly used in war cannot be called 兵器