blue-on-blue

adjective

military of or relating to friendly fireblue-on-blue contacts

Word Origin for blue-on-blue

C20: from the colour used to mark a country's own troops and allies on a military map

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