What does "characterization to the corners" of the process mean? What are process corners?

I have heard this term being used for years, I think its time I knew what it meant. :bonk:

TIA!

In my experience it means the extremes of all tolerances: everything set to the max limits and everthing set to the min limits...
this approach is looking for 'toleracne stackup' issures with your process parameters or inputs. easy to say and tough to do.