Definitions for "Diesis"
A small interval, less than any in actual practice, but used in the mathematical calculation of intervals.
A diesis is a musical interval, usually meaning the difference between three justly tuned major thirds (tuned in the frequency ratio 5:4) and an octave (in the ratio 2:1), equal to 128:125 or about 41.06 cents. In 1/4 comma meantone the diesis retains its value of 128:125, and in other meantone tunings the defect from an octave, whatever it is, from three major thirds is the diminished second, sometimes also called a diesis. It is then the interval involved between pairs of notes which are enharmonic in equal temperament; for instance the interval between E and Fâ™­, however large that is, is a diesis.
Keywords:  dagger, footnote, double, mark, cross
The mark ‡; -- called also double dagger. It is used in printing to indicate a cross reference or footnote