Hell is used to translate four different words in the Scriptures:
Hebrew
Sheol: the abode of the dead, i.e. the grave, whether literally or metaphorically. Corresponds to
Hades in Greek.
Greek
Hades: the abode of the dead, i.e. the grave, whether literally or metaphorically. Corresponds to
Sheol in Hebrew
Tartarus: only used once in the NT by Simon Peter in
2 Peter 2:4 regarding the angels who fell and were cast out of heaven.
Tartarus appears to be some kind of spiritual prison. No reference is made in the Bible to humans every going here.
Tartarus is a common idea in Greek mythology, used to refer to a special section of
Hades; it's an abyss used as a prison for the Titans, elder gods defeated by Zeus and the pantheon in ages past.
Gehenna: The Lake of Fire.
Gehenna is a Hebrew word that has been borrowed and Hellenized. Originally, it referred to the valley of the son of Hinnom (also called Toph or Tophet in the Old Testament, a word that means "drums").
The valley of the son of Hinnom was the common place in which people caused their children to pass through the fire in human sacrifice during the times of the OT. It came to be called Toph(et) or "drums", because, as legend goes, the participants would bang on various drum-like instruments to either conjure the false gods (e.g. Chemosh or Molech) and/or to drown out the cries of screaming babies, toddlers, and young children as they were burned alive on an altar dedicated to the false god.
Eventually, because of it's terrible history, the valley was turned into a refuse pile, a massive garbage dump for the city of Jerusalem. It was lit on fire and continued to burn perpetually.
Hence, this is why
Gehenna is used as a word indicating the Lake of Fire, i.e. a place, metaphorically speaking, perpetually on fire, where the cries of agonized souls are heard screaming in pain as they "die".