(the former) Royal Ulster Constabulary, now superseded by the Police Service of Northern Ireland
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
Examples from the Web for ruc
The letters "RUC" appear on the first page after the synopsis.
The people of those isles call the bird Ruc, and it has no other name.Curious Creatures in Zoology|John Ashton
At the end of the synopsis on the first page are the letters "RUC."