Bitter orange essential oil is from the peel of the fruit of the bitter orange tree. Bitter oranges are mainly used in the west for marmalade. It smells like oranges, but more intense and slightly drier.
Neroli is the distilled essential oil of orange flowers, primarily bitter orange flowers though sweet orange flowers are sometimes used. It has a warm, floral, slightly tart scent that is only slightly citrus-smelling.
I really wouldn't judge either of these two essences from perfume note lists. Check out a store that sells essential oils and smell them for yourself.