Subject: Are gamma and x-rays determined by origin or energy?

I was taught that gamma rays came from the nucleus and x-rays were extra-
nuclear in origin. The diagrams of the electromagnetic spectrum indicate the 
difference is based on the wavelength (with an overlapping zone that can be 
either). What is the most correct means of determining if electromagnetic 
radiation is an x-ray or gamma ray? If the classification is based on the 
origin, is there a good reason to show X and gamma rays separately on the 
diagram of the electromagnetic spectrum? 

Thank you, 

Ken

Re: Are gamma and x-rays determined by origin or energy?