enharmonic modulation

noun

music a change of key achieved by regarding a note in one key as an equivalent note in another. Thus E flat in the key of A flat could be regarded as D sharp in the key of B major

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012