I typically use the word "empathize" to mean, more or less, "to see or understand something from the other person's perspective." In the way I've always used it, one does not have to have actually experienced the problem in question to empathize with someone who is experiencing it, e.g. I've never had a child of mine die, but I like to think I can empathize with the Mom who has. However, I've been told by some that one can't empathize with someone's condition unless one has also experienced it.

  This perspective seems counter-intuitive to me. Using it as a guide suggests "sympathize" is the more correct term. "Sympathize" has connotations of "pity", which in turn suggests, "to feel sorry for." I am a hospice nurse, and I've always seen myself as empathizing -- thoughtfully understanding -- with those in my care, not sympathizing.

What is the correct definition and usage of both "empathy" and "sympathy"?

I typically use "empathize" to mean: "to see or understand something from the other person's perspective." In my use, one needn't have actually experienced the problem in question to empathize with someone who is experiencing it. E.g. I've never had a child of mine die, but I like to think I can empathize with the Mom who has. 

However, some've told me that that one can't empathize with someone's condition without experiencing it. This perspective seems counter-intuitive to me. Using it as a guide suggests "sympathize" is the more correct term. "Sympathize" has connotations of "pity", which in turn suggests, "to feel sorry for." I am a hospice nurse, and I've always seen myself as empathizing -- thoughtfully understanding -- with those in my care, not sympathizing.

What is the correct definition and usage of both "empathy" and "sympathy"?