Gastrectomy); surgical removal of the gall bladder (cholecystectomy); or surgical removal of the pancreas (pancreatectomy), what's the difference?

DIFFERENT ORGANS. Different organ will have different name for surgical operation if you operate on the stomach it will have a different name than the pancreas or the gallbladder they are separate organs is that what you want to know the question was really vague i hope that help.