Source : Webster's Revised Unabridged Dictionary (1913)

Gehenna \Ge*hen"na\ (g[-e]*h[e^]n"n[.a]), n. [L. Gehenna, Gr.
   Ge`enna, Heb. G[=e] Hinn[=o]m.] (Jewish Hist.)
   The valley of Hinnom, near Jerusalem, where some of the
   Israelites sacrificed their children to Moloch, which, on
   this account, was afterward regarded as a place of
   abomination, and made a receptacle for all the refuse of the
   city, perpetual fires being kept up in order to prevent
   pestilential effluvia. In the New Testament the name is
   transferred, by an easy metaphor, to Hell.

         The pleasant valley of Hinnom. Tophet thence And black
         Gehenna called, the type of Hell.        --Milton.

Source : WordNet®

Gehenna
     n : a place where the wicked are punished after death [syn: {Tartarus}]