Hades, Gehenna and Tartarus

"The place in which the terrible punishment here set forth is inflicted, is called hell. This word is found in the English Testament twenty-three times. But in the Greek Testament there are three different words, hades, gehenna and tartarus, signifying different places, all rendered by the one English word, "hell."

Tartarus is used only in the following text: "God spared no the angels that sinned, but cast them down to hell." 2 Peter 2:4. Tartarus is the place into which the evil angels were cast after their rebellion.
 

Thus hades is seen to be the place of the dead, whether righteous or wicked; the place into which they are introduced by death, and from which they are delivered by the resurrection. Those who are in hades are said to be dead. Rev. 20:13. Once, in the English Testament, hades is rendered "grave." 1 Cor. 15:55.

 
Gehenna, on the contrary, is the place where the wicked are to be cast alive with all their members, and to be destroyed soul and body. It is the lake of fire in which the wicked dead are to be punished after their resurrection. Rev. 20:13-15.

---These three places, therefore, though rendered by the one English word "hell," are not to be confounded with one another." 

J.N. Andrews