What does Gehenna refer to?

Self explanatory.

Gehenna is named for the valley behind Jerusalem where refuge and worse was thrown. The gate opening to this valley is named, translated, "The Dung Gate."

So Gehenna is a very bad place.

PS. It is also the valley where certain kings sacrificed children to Moloch.........

JaumeJ is correct in his definition of Gehenna. It is also used figuratively to represent the lake of fire.

There are three words translated as 'Hell' in scripture:

Tartartus - Used once in 2 Peter 2:4 referring to a location under the earth where those angels were sent because of their sins, where they will remain until the great white throne judgment.

Sheol/Hades - A transitional place of torment under the earth where the spirits of the unfaithful dead are kept and where they will be resurrected at the end of the millennial kingdom to stand before God at the great white throne judgment.

Gehenna - géenna (a transliteration of the Hebrew term, Gêhinnōm, "the valley of Hinnom") – Gehenna, i.e. hell (also referred to as the "lake of fire" in Revelation).

Gehenna ("hell"), the place of post-resurrection torment (judgment), refers strictly to the everlasting abode of the unredeemed where they experience divine judgment in their individual resurrection-bodies. Each of the unredeemed receives one at the Great White Throne Judgment (Rev 20:11-15), i.e. a body that "matches" their capacity for torment relating to their (unique) judgment.

While Tartartus and Hades are said to be located under the earth, the location of Gehenna/lake of fire, is not revealed.

Four words are translated to "hell" ~ Sheol, Gehenna, Tartarus, and Hades.

The Greek word Gehenna (also spelled Geenna) occurs 12 times in the
New Testament, and is always translated "hell" in the King James Version.
The word is used only one time in the New Testament outside the first three
Gospels, in James 3:6 where it is used metaphorically about the harm caused
by a vile human tongue. Whether Gehenna was used by Jesus to typify what
a true Hell is like may be debated. What is beyond debate is that Gehenna
was a known place on the south side of Jerusalem familiar to all who heard
Jesus speak. The word Gehenna is the Greek spelling of the Hebrew words
ge hinnom, meaning "valley of Hinnom." A quick search of a concordance
for the word Hinnom will find the 11 verses referring to this location in the
Old Testament. From these verses you will readily see the evils that happened
in this valley, and understand how it became thought of as a horrible place
by Jews. The valley of Hinnom, south of Jerusalem, was the place in ancient
times where idolatrous Israelites burned their children alive as sacrifices to
Molech and Baal. (Molech is sometimes spelled Moloch). It was also referred
to as Tophet, which means a place of fire. Gehenna is never used in the Old
Testament to mean anything other than the place outside Jerusalem with
which every Jew was familiar. source

Are the terms mistakenly conflated as being the afterlife of punishment in contemporary Christian tradition?

No, these are individual places of punishment. It is said that the angels were sent to Tartartus, which is a different place from Hades and Gehenna. And example of Hades can be found in 'the rich man and Lazarus.'

"One day the beggar died and was carried by the angels to Abraham’s side. And the rich man also died and was buried. In Hades, where he was in torment, he looked up and saw Abraham from afar, with Lazarus by his side."

At the end of the thousand years (millennial kingdom) we also have the spirits of those who will have been in Hades being released and receiving resurrected bodies at the great white throne judgment. These are the people who will have been accumulating there throughout all of history.

To be clear, those angels that were sent to Tartartus are still there and will be judged at the great white throne judgment.

Those who have died without faith throughout all of history, their spirits are currently in Hades in torment in flame, where they will also be released to stand before God at the great white throne judgment.

according to scripture, no one has yet been put into the Gehenna/lake of fire also called the second death. It appears that its first recipients will be the beast and the false prophet (Rev.19:20). At the great white throne judgment, anyone's name not found in the book of life will be thrown into the lake of fire. Death and Hades (personified) will also be thrown into the Gehenna/lake of fire.

That suggests that they are being mistakenly conflated

If it is self-explanatory, then there is no need for this question is there?

That is a false and misleading statement. *Gehenna* was was not loosely used by Christ with reference to the Lake of Fire. Indeed this term was specifically used for the Lake of Fire and eternal damnation. The eternality is expressed by "where their worm dieth not and the fire is not quenched".

A rubbish dump would be meaningless in this context.

MARK 9: WARNINGS ABOUT HELL, GEHENNA, THE LAKE OF FIRE
41 For whosoever shall give you a cup of water to drink in my name, because ye belong to Christ, verily I say unto you, he shall not lose his reward.
42 And whosoever shall offend one of these little ones that believe in me, it is better for him that a millstone were hanged about his neck, and he were cast into the sea.
43 And if thy hand offend thee, cut it off: it is better for thee to enter into life maimed, than having two hands to go into hell [GEHENNA], into the fire that never shall be quenched:
44 Where their worm dieth not, and the fire is not quenched.
45 And if thy foot offend thee, cut it off: it is better for thee to enter halt into life, than having two feet to be cast into hell [GEHENNA], into the fire that never shall be quenched:
46 Where their worm dieth not, and the fire is not quenched.
47 And if thine eye offend thee, pluck it out: it is better for thee to enter into the kingdom of God with one eye, than having two eyes to be cast into hell [GEHENNA] fire:
48 Where their worm dieth not, and the fire is not quenched.

Strong's Exhaustive Concordance
gehenna, hell.
Of Hebrew origin (gay' and Hinnom); valley of (the son of) Hinnom; ge-henna (or Ge-Hinnom), a valley of Jerusalem, used (figuratively) as a name for the place (or state) of everlasting punishment -- hell.

No, these different locations are not being conflated. And God does not do anything mistakenly.

The context of the scriptures puts Sheol/Hades under the earth. Once the unrighteous dead are released from Hades to stand at the great white throne judgment, they are then cast into the lake of fire.

This present heaven and earth are going to be destroyed. Since Tartarus, Hades and the Abyss are located under the earth, then those locations will also be destroyed. The lake of fire however, is the final place of punishment, which does not reside on this earth.

Why do you ask a question, but are already determined to reject the true answer. That is what I have noticed about you since you've come on to this site.

Named Locations under the earth = The Abyss, Sheol/Hades, Tartartus. These locations will cease to exist when this present earth is destroyed.

Gehenna/lake of fire = A place of everlasting fire created for Satan and his angels, including all humanity whose names are not found written in the book of life.

I don't think Vicky was asking if God had done anything mistakenly.
She was asking if the terms are mistaken in contemporary Christian tradition.

The short answer is yes.

The devil has a pitchfork & wears red tights

Thank you for clearing another misunderstanding, Lucy.

But the devil wears a suit and tie.

This certain dump was always burning as well....

There are three Greek words translated "hell": Geenna, Hades, and Tartaroo.

Matthew 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.


1067

1067 geenna {gheh'-en-nah}

of Hebrew origin 01516 and 02011; TDNT - 1:657,113; n f

AV - hell 9, hell fire + 3588 + 4442 3; 12

1) Hell is the place of the future punishment call "Gehenna" or
"Gehenna of fire". This was originally the valley of Hinnom,
south of Jerusalem, where the filth and dead animals of the
city were cast out and burned; a fit symbol of the wicked and
their future destruction.


This word is the type of hell that is the final punishment, known as the lake of fire in Revelation.




Matthew 16:18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.


86

86 hades {hah'-dace}

from 1 (as negative particle) and 1492; TDNT - 1:146,22; n pr loc

AV - hell 10, grave 1; 11

1) name Hades or Pluto, the god of the lower regions
2) Orcus, the nether world, the realm of the dead
3) later use of this word: the grave, death, hell

In Biblical Greek it is associated with Orcus, the infernal regions,
a dark and dismal place in the very depths of the earth, the common
receptacle of disembodied spirits. Usually Hades is just the abode of
the wicked, Lu. 16:23, Rev. 20:13,14; a very uncomfortable place. TDNT.


This is not the same hell, but is where the unsaved dead dwell until the day of judgement. Its known as purgatory, death and the grave.

This "hell" is what is cast into and destroyed by the other "Hell" ie: the lake of fire:


Revelation 20:14 And death and hell were cast into the lake of fire. This is the second death.



2 Peter 2:4 For if God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment;

5020

5020 tartaroo {tar-tar-o'-o}

from Tartaros (the deepest abyss of Hades);; v

AV - cast down to hell 1; 1

1) the name of the subterranean region, doleful and dark, regarded by
the ancient Greeks as the abode of the wicked dead, where they suffer
punishment for their evil deeds; it answers to Gehenna of the Jews
2) to thrust down to Tartarus, to hold captive in Tartarus


This is the third word and is a holding place for very evil souls. It is also known as the pit in Revelation where satan is held for 1000 years. It is a special place within Hades.

Once again about the valley behind Jerusalem, it was taken, its name that is, from the valley of Hinnom, if this helps any.