Ogre

Ogres are not known to exist anywhere in the world of Guild Wars, despite the fact that the following items can be found:
 * Ogre-Slaying Knife
 * weapon upgrade "of Ogreslaying"
 * weapon modifiers providing special bonuses against Ogres

Trolls, Ettins and Giants all fit various meanings of the common term "Ogre". However they are not Ogres by the game mechanics of Guild Wars.