1) With respect to harmony 
Har·mon'ic·al·ly (-ĭ*k a l*lȳ) adverb 1. In an harmonical manner; harmoniously. 2. In respect to harmony, as distinguished from melody ; as, a passage harmonically correct. 3. (Math.) In harmonical progression. 
[adv] - with respect to harmony
harmonically 1. Of or relating to harmony. 2. Pleasing to the ear. 3. Characterized by harmony. 4. Of or relating to harmonics.
adverb with respect to harmony; `harmonically interesting piece`