ON prep. 2 definitions
Denoting performance or action by contact with the surface, upper part, or outside of anything; hence, by means of; with; as, to play on a violin or piano. Hence, figuratively, to work on one's feelings; to make an impression on the mind.
ORGAN n. 3 definitions
An instrument or medium by which some important action is performed, or an important end accomplished; as, legislatures, courts, armies, taxgatherers, etc., are organs of government.