"Spellbound" is the name of Dai Vernon's routine which was published in "The Stars of Magic" where a copper coin changes to a silver coin and back. It is based on Edward Victor's "The Changing Coin," which is turn may have been based on a routine I read in either The Sphinx or Mahattma from around 1905.
I beleive that the term you speak of refers to a coin slight called the "spellbound change". It is described in full detail in Bobo's book and by David Roth in his book as well as his video series. (And I'm sure in thousands of other coin book/videos)