"Gehinnom is the Hebrew name; Gehenna is Yiddish." Gehinnom - Judaism 101 websourced 02-10-2010.
"The place of spiritual punishment and/or purification for the wicked dead in Judaism is not referred to as Hell, but as Gehinnom or She'ol." HELL - Judaism 101 websourced 02-10-2010.
Kohler, Kaufmann; Ludwig Blau (1906). "Gehenna". Jewish Encyclopedia. "The place where children were sacrificed to the god Moloch was originally in the 'valley of the son of Hinnom,' to the south of Jerusalem (Josh. 15:8, passim; II Kings 23:10; Jer. 2:23; 7:31–32; 19:6, 13–14). For this reason the valley was deemed to be accursed, and 'Gehenna' therefore soon became a figurative equivalent for 'hell.'"
Kohler, Kaufmann; Ludwig Blau (1906). "Gehenna: Sin and Merit" Jewish Encyclopedia: "It is frequently said that certain sins will lead man into Gehenna. The name 'Gehenna' itself is explained to mean that unchastity will lead to Gehenna (Eruvin (Talmud)|'Er. 19a); so also will adultery, idolatry, pride, mockery, hypocrisy, anger, etc. (Sotah (Talmud)|Soṭah 4b, 41b; Ta'anit (Talmud)|Ta'an. 5a; Bava Batra 10b, 78b; Avodah Zarah 18b; Nedarim 22a)." Catholic Encyclopedia: Hell: "[I]n the New Testament the term Gehenna is used more frequently in preference to hades, as a name for the place of punishment of the damned.... [The Valley of Hinnom was] held in abomination by the Jews, who, accordingly, used the name of this valley to designate the abode of the damned (Targum Jonathan, Gen., iii, 24; Henoch, c. xxvi). And Christ adopted this usage of the term."
newadvent.org
Kohler, Kaufmann; Ludwig Blau (1906). "Gehenna: Sin and Merit" Jewish Encyclopedia: "It is frequently said that certain sins will lead man into Gehenna. The name 'Gehenna' itself is explained to mean that unchastity will lead to Gehenna (Eruvin (Talmud)|'Er. 19a); so also will adultery, idolatry, pride, mockery, hypocrisy, anger, etc. (Sotah (Talmud)|Soṭah 4b, 41b; Ta'anit (Talmud)|Ta'an. 5a; Bava Batra 10b, 78b; Avodah Zarah 18b; Nedarim 22a)." Catholic Encyclopedia: Hell: "[I]n the New Testament the term Gehenna is used more frequently in preference to hades, as a name for the place of punishment of the damned.... [The Valley of Hinnom was] held in abomination by the Jews, who, accordingly, used the name of this valley to designate the abode of the damned (Targum Jonathan, Gen., iii, 24; Henoch, c. xxvi). And Christ adopted this usage of the term."
uskonkirjat.net
raamattu.uskonkirjat.net
Kohler, Kaufmann; Ludwig Blau (1906). "Gehenna". Jewish Encyclopedia. "The place where children were sacrificed to the god Moloch was originally in the 'valley of the son of Hinnom,' to the south of Jerusalem (Josh. 15:8, passim; II Kings 23:10; Jer. 2:23; 7:31–32; 19:6, 13–14). For this reason the valley was deemed to be accursed, and 'Gehenna' therefore soon became a figurative equivalent for 'hell.'"