gehenna - Gehenna refers to a valley just outside Jerusalem. The word is derived from the Hebrew Ge-Hinnom, the valley of Hinnom (Joshua 18:16). At the time of Jesus this valley was what we might call the city dump—the place where garbage, trash and refuse were thrown and consumed in the fires that constantly burned there. The carcasses of dead animals—and the bodies of despised criminals—were also cast into Gehenna to be burned. Jesus used this particular location and what took place there to help us understand the fate the wicked and unrepentant will suffer in the future. (from "Heaven and Hell")
Jesus uses this term here:
Mat 5:30 And if thy right hand offend thee, cut it off, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell.
This term is used in Mat_5:22, Mat_5:29-30 (2), Mat_10:28, Mat_18:9, Mat_23:15, Mat_23:33, Mar_9:43, Mar_9:45, Mar_9:47, Jam_3:5-6
tartaroo - used only once in the Bible (2 Peter 2:4), where it refers to the place where the fallen angels, or demons, are restrained awaiting their judgment. The Expository Dictionary of Bible Words explains that tartaroo means "to confine in tartaros" and that "Tartaros was the Greek name for the mythological abyss where rebellious gods were confined" (Lawrence Richards, 1985, "Heaven and Hell"). Peter used this reference to contemporary mythology to show that the sinning angels were "delivered ... into chains of darkness, to be reserved for judgment." Fallen angels are in a condition or place of restraint awaiting their ultimate judgment for their rebellion against God and destructive influence on humanity. Tartaroo applies only to demons. Nowhere does it refer to a fiery hell in which people are punished after death.
hades - "The Greek word Hades ... is sometimes, but misleadingly, translated 'hell' in English versions of the N[ew] T[estament]. It refers to the place of the dead ... The old Hebrew concept of the place of the dead, most often called Sheol ... is usually translated as Hades, and the Greek term was naturally and commonly used by Jews writing in Greek" (1992, Vol. 3, p. 14, "Hades, Hell").
Both sheol and hades refer to the grave. A comparison of an Old Testament and a New Testament scripture confirm this. Psalm 16:10 says, "For You will not leave my soul in Sheol, nor will You allow Your Holy One to see corruption." In Acts 2:27 the apostle Peter quotes this verse and shows that it is a reference to Christ. Here the Greek word hades is substituted for the Hebrew sheol.
Where did Christ go when He died? He went to the grave. His body was placed in a tomb belonging to Joseph of Arimathea. The two passages, in Psalms and Acts, tell us Jesus' flesh did not decay in the grave because God resurrected Him.
The majority of scriptures that use the term hell are simply talking about the grave, the place where everyone, whether good or evil, goes at death. The Hebrew word sheol is used in the Old Testament 65 times. In the King James Version it is translated "grave" 31 times, "hell" 31 times and "pit" three times. (from "Heaven and Hell")
In addition, there is the "lake of fire":
Rev 20:14 And death and hell were cast into the lake of fire. This is the second death.
Rev 20:15 And whosoever was not found written in the book of life was cast into the lake of fire.
The lake of fire is what Christ was referring to when he used the term "gehenna". Wicked people who refuse to accept Christ will surely go there, but they will burn up and die. That's why it's called "the second death".
Mat 10:28 And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell (gehhena).
Note that Jesus Christ says that soul and body will be destroyed in Gehenna. So I would disagree that there is no hell, but would agree that people are not tortured eternally.
Hell as the second death or a true death has been my reading of the text.
Douglas, could you elaborate on this some more? Thank you for the scripture references and explanation.