Artillery is a branch of service that supports the fighting troops by means of fire support (and by observations). Fire support can be given by direct or indirect fire from guns or rockets. Artillery is not a weapon but a class.
Its scope varies somewhat between nations but broadly it comprises field artillery, anti-aircraft artillery and target acquisition. Historically it also included coast artillery. In field artillery guns generally, fall into two categories – Howitzers and Guns. The key difference is that the maximum elevation angle for a Gun is 45 degrees, whereas for a Howitzer it is greater than that, typically around 70 degrees, this enables upper-register fire, ie the trajectory goes a lot higher, which is important in mountainous terrain.
In terms of Artillery, there are 3 main categories: Howitzers, Guns, and Mortars. Most People Fail to Differentiate between the Three. Especially between Howitzers and Guns/Cannons since they are quite similar in appearance and Working.
So What Are The Differences Between Various types of Artillery?
Not Much. Howitzers, Guns and Mortars are all a type of Artillery.
There are three main types of artillery, distinguished by muzzle velocity and firing trajectory.
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Gun/Cannon: High velocity, low angle, direct fire

- Howitzer: Medium velocity, medium angle, direct or indirect fire

- Mortar: Low velocity, high angle, indirect fire

Generally speaking, the lower the velocity, the lower the stress the shell experiences. Therefore the shell walls can be thinner, allowing for a larger bursting charge or other filler.
However, the higher the velocity, the better the armour penetration.
This is why tanks have guns, while most artillery units are equipped with howitzers or mortars.
Additional to this graphic – barrels are, typically, the heaviest part of the weapon system. Because of this, and because muzzle velocity cannot be raised without increasing barrel length very efficiently, guns have longer barrels than howitzers, and are thus typically much heavier.
Also, because the projectile is spinning at a speed relative to the muzzle velocity, and because centrifugal force would cause the shell to fall apart, higher velocity guns require more steel “padding” around their HE core than slower mortars. This, in effect, makes a 120mm Mortar shell impact comparable to that of a 155mm guns, while weighing about 1/2 the weight.