whoo boy, here we go.
In a .357 Magnum revolver, you can safely fire:
.357 Magnums
.38 Special +Ps
.38 Specials
.38 Long Colts.
These all fire the same diameter bullets, roughly .355 to .358 diameter.
You cannot safely fire, and in fact, they will not load:
.38 S&Ws, as the .38S&W is actually a .38 caliber, not a .35 caliber, round.
The .38 Special is a longer version of the .38 Long Colt, (which, IIRC, but don't quote me on it, was just a longer version of the very long dead .38 Colt), and the .357 Magnum just a longer version of the .38 Special.
The .38 S&W was an entirely different round and is compatible with only the .38 S&W.