Glock is a brand. 9mm is a caliber size. So, there is no difference between a 9mm glock and a 9mm of another brand as far as caliber size.
9mm
The 9mm round in loaded with a bullet diameter of .356"in.
9mm= .355 45 ACP = .452
9mm = .355
A 9mm circle can be represented by the diameter of a standard 9mm bullet, which is commonly used in handguns. This diameter is often associated with ammunition such as the 9mm Parabellum, widely used in both military and civilian contexts. Additionally, a 9mm circle can be visualized as the size of a small coin, like a dime, which measures approximately 17.91mm in diameter, making a 9mm circle roughly half that size.
size 9mm splin
9mm
There are SEVERAL 9mm cartridges- the most common is probably the 9mm Parabellum (9mm Luger). A 9mm Parabellum BULLET (not cartridge) is typically slightly smaller than a .38 Special bullet- .356 instead of .357. The 9mm is frequently (not always) lighter- and shorter. Other 9mm cartridges (such as the 9mm Makarov) will have different bullets.
You can convert 9mm to 0.354331 inches using a mm to inches converter.
Most are in .380 ACP caliber. Sometimes called 9mm Short in Europe (or 9mm Corto or 9mm Kurz) What is marked on yours?
You cannot re-size 380 brass with a 9mm sizing die, nor can you size 9mm brass with a 380 die. You can use the the bullet seating dies back and forth. But you'll need to get sizing dies in both 380 and 9mm. The shell holder and primers are the same for both.