The place we call "hell" goes by a few different names in the Bible:
Hades: the Greek place of the dead. Souls in Hades were called “shades.” It’s sort of a neutral place, but by the time of Homer and Pythagoras people were developing ideas about rewards and punishments in Hades.
Sheol: in early Jewish thought, Sheol is an underworld/nether-region. It was the common place of the dead, where all led an “unenviable,” and “gloomy” existence. The Septuagint (early Greek version of the Old Testament) called Sheol “Hades” because of the similarity between the two places. As ideas about resurrection developed, Sheol/Hades became a temporary abode of dead, where souls waited to be brought back to bodily life. One interesting view held that bodies went to Sheol/Hades and souls went to heaven, and were united in a general resurrection.
In the Bible, Sheol/Hades isn’t necessarily a place of punishment, but a place of safe-keeping for the dead. It and Death will be thrown into the lake of fire at the resurrection (Rev. 20:13).
Gehenna: This is the bad one. Gehenna refers to the Valley of Hinnom outside of Jerusalem, where folklore held that people who worshiped the god Molech sacrificed children. It is also thought that trash (and corpses) were burned there consistently. This appears to be a medieval rabbinic tradition, and there’s not a lot of archaeological evidence to support it. Regardless, in the imagination of people in Jesus’ time (and following), this was a place where bad things happened. Gehenna names all that is opposed to God’s kingdom.
Matthew chapters 5, 10, 18, and 23 all mention Gehenna, as well as Mark 9, Luke 12, and James 3.
Hell: a word with Germanic/Norse origins. In folklore/legend there was a place called “Hel” that was the abode of the dead and a figure named Hel who ruled there. The King James Version of the Bible translated Hades, Gehenna, and Sheol all as “hell.”
(For more information on all of the above, see The Anchor Bible Dictionary, a series of dense reference volumes edited by David Noel Freedman and a million of his closest friends – published by Doubleday, 1992.)
