1911 Encyclopædia Britannica/Tophet

TOPHET, or Topheth (תוֹפֶת), the name given in 2 Kings xxiii. 10; Jer. vii. 31, to a spot in the valley of Ben Hinnom near Jerusalem where the Hebrews in the time of Ahab and Manasseh offered children to Molech and other heathen gods. Josiah “defiled” it as part of his reforming activity, and it became a place for the bestowal and destruction of refuse, and a synonym for Gehenna (Isa. xxx. 33; Jer. vii. 32).

The uncertain etymology of the word is discussed in the Ency. Bib., s.v. “Molech,” § 3, “Topheth.”