n. — Military
a nickname for the Princess Patricia's Canadian Light Infantry regiment.
Type: 1. Origin — The Patricias were formed at the outbreak of WWI by a Montreal merchant who was granted permission to name the regiment after Princess Patricia of Connaught, a granddaughter of Queen Victoria (see Image 1, see the first 1914 quotation). The regiment recruited, however, not just from Montreal but from throughout Canada. Soon after, it became a Regular Force regiment of the Canadian Army. The PPCLI served in both World Wars, the Korean War, and numerous NATO operations. As a result, the regiment, which is active today, has acquired Cultural Significance, especially during its missions in the World Wars and their role in Canada's coming of age (see National Defence and the Canadian Forces reference).
The regiment was originally called by its full title (see, e.g. the 1914 quotation), but soon after became known as the "Princess Patricias" (see the 1915 quotation). Thereafter, both Princess Patricias and Patricias were used interchangeably, and sometimes Princess Pats (see the 2008 quotation). Patricias is also used by military personnel in certain instance in lieu of the full name (see, e.g. the 2004 quotation), so the nickname has acquired more formal undertones, comparable to Mountie, than is otherwise customary. The form remains most prevalent in Canada (see Chart 1).
See also COD-2, s.v. "Patricias", which is marked "Cdn".
See also: Princess Pats
Images:

Image 1: King George V holds an investiture in Valenciennes, 5 December 1918, of the 7th Canadian Brigade (Royal Canadian Regiment, Princess Patricia's Canadian Light Infantry, 42nd and 49th Battalions (Source: Wikimedia Commons. Photo: McLellan, David, Second Lieutenant) 
Chart 1: Internet Domain Search, 17 Aug. 2012