HARMONIC. As an adjective, it signifies in general any thing belonging to harmony; though, in our language, the adjective is more properly written harmonical. In this sense it may be applied to the harmonical divisions of a monochord; or, in a word, to consonances in general. As a substantive neuter, it imports all the concomitant or accessory sounds which, upon the principles resulting from the experiments made on sonorous bodies, attend any given sound whatever, and render it appreciable. Thus all the aliquot parts of a musical string produce harmonical sounds, or harmonics.