Why are weapons not called guns?

Nomenclature is interesting. I have no idea. weapon can cover any thing from a fire pace poker to a nuclear bomb. Gun seem to refer specifically to kinetic weapons with propelled projectiles. There is also the language of the art. The military seems to have chosen "weapon" as the language of the military for soldier issued guns. So now I think we are following precedence and not wanting to appear as an outsider "Maintain your WEAPON soldier" is clearly understood by military members not to mean "your fire place poker needs to be polished".

Lots of good comments here aleready on the general definitions. The Marine Corps specific penchant for calling firearms especially individual arms 'weapons' and sometimes more specific names "rifle" "pistol" etc. probably arises out of a desire for specificity and clarity. Artillery pieces, howitzers, are called "guns" so are machine guns for more rapid speech, I would hazard a guess the Corps instituted this lexical difference to make it clear when a Sgt tells a LCpl "Go get on your gun" the LCpl will know the Sgt means the Machinegun rather than the rifle.

Because 'guns' is how you address a Gunners mate? Seriously, I think that might be because not all weapons are "guns".

Guns are not weapons. Guns are tools. I have made it a point throughout my career in law enforcement and the military to not call "firearms" weapons.

When I travel overseas I always carry a Cross ink pen with small strips of skateboard tape on it. It is great tool if I need to stab somebody. Nobody questions it at the airport. Why? Because it is pen. I'll use it as a weapon, but when I am done it is a pen. The same can be said for a gun. The only difference is it starts out as a tool for for protection.

What a question. why don't we call oranges tomatoes?

Do they still teach basic trainees that poem of "this is my weapon, and this is my gun; my weapon's for killing and my gun is for fun" when they tell them never to call their rifle a "gun"? Something tells me probably not.

Who cares, this is not relevant.

A gun, by common military definition, is generally accepted as a large bore, crew served weapon. This includes smooth bore and rifled cannons and artillery pieces (and naval "guns"). A weapon is something man portable. True, weapons can be crew served, but they are not "large bore". Mortar systems are admittedly a gray area and have been referred to as gun-mortars in the past (talking a few hundred years).