Short answers, pulled from the story.
The word hell derives from Old English hel or helle, first attested around 725 AD to refer to a nether world of the dead. It traces back to a reconstructed Proto-Germanic root meaning "concealed place" or "the underworld," which itself comes from the Proto-Indo-European root meaning "to cover" or "to conceal," the same root that gives English the word cellar.
Christianity, in many of its forms, and Islam teach that hell is eternal, with the Catholic Church's 1993 Catechism describing it as permanent separation from God. Judaism, Buddhism, Hinduism, Jainism, and Zoroastrianism generally treat hell as temporary, with souls eventually purified or destroyed. The maximum stay in Jewish Gehinnom is traditionally said to be 12 months.
One of the oldest detailed descriptions of hell is found in the Kathavatthu, an early Buddhist text written around 250-100 BCE, which argues that hell is a state resulting from bad action. Egyptian belief as early as 1500 BCE also asserted that the dead would be judged and punished, though the Egyptian punishment ended in annihilation rather than ongoing torment.
In Islam, hell is called Jahannam, a word related to the Hebrew gehinnom. It is divided into seven layers filled with blazing fire and boiling water. The Quran's mention of seven gates inspired Muslim commentators to develop a system of seven stages, each named by a different Quranic term for hell and assigned to a different category of sinner.
No. Buddhist and Tibetan Buddhist traditions feature an equal number of hot and cold hells. Early Christian texts, including the Apocalypse of Paul from the early third century and the Venerable Bede's Vision of Dryhthelm from the seventh century, already included cold in their depictions of hell or purgatory. Dante's innermost circle of hell is a frozen lake, not a furnace.
In the Divina commedia, set in the year 1300, Dante Alighieri maps hell as nine concentric rings leading deeper into the Earth until Satan himself is found trapped in the frozen lake of Cocytus at the center of the world. Dante's guide through hell is the Roman poet Virgil, who as a virtuous pagan is confined to Limbo at hell's edge rather than condemned to the lower circles.