Older C compilers would truncate a variable name if it was too long, so VeryLongGlobalConstantInsideALibraryInSeconds
might accidentally collide with VeryLongGlobalConstantInsideALibraryInMinutes
.
Legend says that they used to do it after a single letter with Dennis declaring "26 variables ought to be enough for anyone".
I am in this picture and I don't like it. I accept it because chances are I really did make a bad decision but I still don't like it.