Explosive Remnants of War (ERW) means explosive ordnances that are left behind in the post-conflict environment. It does not mean landmines, but includes instead all the other forms of conventional explosive weaponry – mortar bombs, rockets, grenades, artillery shells and air-dropped bombs. The term ERW now formalised in the UN CCW Protocol V as unexploded ordnance (UXO) and abandoned explosive ordnance (AXO).
Source: Explosive remnants of war and mines other than anti-personal mines, Global Survey 2003-2004, Landmine Action (UK), Actiongroup Landmine.de Mines Action Canada