Source : Webster's Revised Unabridged Dictionary (1913)

Ogre \O"gre\, n. [F., fr. Sp. ogro, fr. L. Orcus the god of the
   infernal regions; also, the lower world, hell.]
   An imaginary monster, or hideous giant of fairy tales, who
   lived on human beings; hence, any frightful giant; a cruel
   monster.

         His schoolroom must have resembled an ogre's den.
                                                  --Maccaulay.

Source : WordNet®

ogre
     n 1: a cruel wicked and inhuman person [syn: {monster}, {fiend},
          {devil}, {demon}]
     2: (folklore) a giant who likes to eat human beings