Blue Ensign
noun
an ensign having the Union Jack on a blue background at the upper corner of the vertical edge alongside the hoist: flown by Royal Navy auxiliary vessels, and, with some extra distinguishing mark or insignia, by certain yacht clubsCompare Red Ensign, White Ensign
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