Each time I see this subject line go by, a little voice in my head says: "It's like pornography, you'll know it when you see it." But I think for a serious answer, the one from Jovo is about as good as you're likely to get. I think 'Fine Art' might be a useful phrase to differentiate one's intentions, as in "Yes I'm a photographer, but I don't do weddings or bar mitzvahs, I'm a fine art photographer" but a rigorous, universally agreed on definition is just not likely.