Jen, Yes the N means the number of lymph nodes involved. There's a section here with all the definitions listed, just try the search engine when you get time. It will help. Keep posting and people on here will be able to help. Your Mom is truly blessed to have such caring daughters. My sons were such strengths for me throughout my treatments. Don't know how I would of gotten through without them. Take care and know your Mom and your family are in my thoughts and prayers. Linda