Apotome
A*pot"o*me\, n. [Gr. ? a cutting off, fr. ? to cut off; ? from + ? to cut.]1. (Math.) The difference between two quantities commensurable only in power, as between [root]2 and 1, or between the diagonal and side of a square. 2. (Mus) The remaining part of a whole tone after a smaller semitone has been deducted from it; a major semitone. [Obs.]