Yahoo Web Search

Unexploded ordnance (UXO, sometimes abbreviated as UO), unexploded bombs (UXBs), and explosive remnants of war (ERW or ERoW) are explosive weapons (bombs, shells, grenades, land mines, naval mines, cluster munition, and other munitions) that did not explode when they were employed and still pose a risk of detonation, sometimes many decades after they were used or discarded. Wikipedia