Typically, they're about even.. the bullet diameter .38 Special is larger by a negligible amount - .357, as opposed to .356 of the 9mm Parabellum.
9mm IS the caliber. If you mean what is it equivalent to, it is approximately the same as a .38.
Yes you can.
No, you cannot.
the are also chambered for the 38 caliber, 9mm caliber and 22 caliber
Close, but no. A .38 Special fires a .357 inch diameter bullet, 9mm Parabellum fires a slightly smaller bullet, but with more force. The .38 is a rimmed revolver cartridge, and the 9mm is a rimless automatic pistol cartridge.
The 380 ACP, also known as the 9mm Short, 9x17, 9mm Browning, 9mm Kurz and 9mm Corto uses a .355 diameter bullet. The 38 special uses a .357 diameter bullet. Additionally, the 380 ACP is designed for a semi-automatic and the .38 special is designed for a revolver.
One would think that .380 ACP and .38 Special would be the same size--namely 38-hundredths of an inch. But there can be some flexibility in stated caliber and actual caliber. Long story short, .380 ACP is the same diameter as a 9mm, roughly .355 caliber. .38 Special is basically .357 caliber.
You'd think they would be--right? Depending on the tolerances of a particular weapon, you might be able to use SIMILAR projectiles. A .380 caliber is actually has a .355 caliber projectile--so does a 9mm. The typical .38, as in 38 Special is .357 caliber. So, when all is said and done, .355 caliber is smaller than .357 caliber. No, they are not the same, but close.
About .36 caliber. The 9mm family of calibers normally uses a bullet that is .356 diameter. This is the same as the .380 and nearly the same as the .38 Special, whose "nominal" calibers are quite different from their actual bullet diameter when measured.