A Dictionary of Music and Musicians/Head-voice
HEAD-VOICE in contradistinction to chest-voice. This term is applied indifferently to the second or third register. Its range is absolutely indefinable, seeing that many or most of the notes naturally produced 'from the chest' may also be produced 'from the head'; or, in other words, that the different 'registers' of every voice may be made to cross each other. [See Chest-voice; Falsetto.]
[ J. H. ]