Ogre

Although no monsters are explicitly called Ogres in-game, it has been experimentally verified that Ettins and Yeti are in fact Ogres. The following weapons inflict extra damage against Ogres:
 * Ogre-Slaying Knife
 * Weapons with the "of Ogreslaying" upgrade

Trolls, Giants, Oni and the beasts ridden by Summit Beastmasters and Summit Giant Herders all fit various meanings of the common term "Ogre". However they are not Ogres by the game mechanics of Guild Wars.