TONIC

(From Tone.) In Music, the principal note of the key. It is the chief sound upon which all regular melodies depend, and in which they all terminate. Its octaves, both above and below, are equally called by the same name. It is, however, to be understood that the termination here alluded to has relation only to the chief melody, or to its ba , inasmuch as the inner or mean parts of the harmony conclude on the third or mediant, and the fifth or dominant. [s. 1266]