|Easton's Bible Dictionary|
(composed of the names of two Syrian idols), the name of a place in the valley of Megiddo. It is alluded to by the prophet Zechariah (12:11) in a proverbial expression derived from the lamentation for Josiah, who was mortally wounded near this place (2 Chronicles 35:22-25). It has been identified with the modern Rummaneh, a village "at the foot of the Megiddo hills, in a notch or valley about an hour and a half south of Tell Metzellim."
Int. Standard Bible Encyclopedia
ha-dad-rim'-on, had-ad-rim'-on (hadhadh rimmon): A name which occurs, along with Megiddon, in Zechariah 12:11. It was long thought that this was a place in the plain of Megiddo, and that the mourning referred to was that for Josiah, slain in battle with Pharaoh-necoh (2 Kings 23:29). This last, however, was certainly at Jerusalem. Jerome (Commentary on Zechariah) identifies Hadadrimmon with Maximianopolis, a village near Jezreel, probably Legio, the ancient Megiddo. Possibly, however, the form "Hadadrimmon" has arisen through the combination of two divine names; and the weeping may be that for Tammuz (Ezekiel 8:14), with whom the old Semitic deity had become confused in the popular mind.
Hadad-rimmon (1 Occurrence)
Zechariah 12:11 In that day there will be a great weeping in Jerusalem, like the weeping of Hadad-rimmon in the valley of Megiddon. (BBE DBY)