A Dictionary of Music and Musicians/Tonic
TONIC. The name given in modern music to the Key-note, i.e. the note from which the key is named. The functions of the tonic are in all respects identical with those of the final of the ancient modes. The tonic harmony is the common chord or triad, major or minor as the case may be, which is built upon the key-note as its bass. The rule that every composition must end with this harmony in some shape or other is probably the only law of music which has remained in full force through all the changes from the ancient to the modern styles. Its application is so universal that only one exception occurs readily to the mind, that of a song by Liszt, in which the effect of the innovation is so unsatisfactory that it is extremely improbable that it will often be repeated.
[ M. ]