The problem is, "1911" is EXTREMELY in-exact, so there's no way to tell you exactly what it is.
It would be sort of like saying, "What exactly is a car?" I could tell you it's a motorized vehicle, but even some things that would normally be assumed, such as four wheels, two of which are driven by an internal combustion engine, etc., don't really apply, anymore.
"1911" has really come to mean a gun with a certain appearance, but nothing in particular can be assumed about materials, chambering, capacity, specifications, etc., based only on "1911".
The only two "1911s" about which there is anything exact are the M1911 and the M1911A1. You can find drawings with materials, dimensions, heat-treat specs, etc. Everything else is a crap-shoot.