part exchange n 1. (Commerce) a transaction in which used goods are taken as partial payment for more expensive ones of the same type 2. (Commerce) (as modifier): part-exchange deals. Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014