|Easton's Bible Dictionary|
(2 Samuel 12:30, Hebrews, R.V., "their king;" Jeremiah 49:1, 3, R.V.; Zephaniah 1:5), the national idol of the Ammonites. When Rabbah was taken by David, the crown of this idol was among the spoils. The weight is said to have been "a talent of gold" (above 100 lbs.). The expression probably denotes its value rather than its weight. It was adorned with precious stones.
Int. Standard Bible Encyclopedia
mal'-kam (malkam, "their king"; the King James Version Maleham):
(1) A chief of the Benjamites, son of Shaharaim (1 Chronicles 8:9).
(2) The name of an idol as well as the possessive pronominal form of melekh, "king" (2 Samuel 12:30 the Revised Version margin; Jeremiah 49:1, 3 Septuagint Melchol); Zechariah 1:5). In Amos 1:15 it appears to be best translated "their king," as in both the King James Version and the Revised Version (British and American). Only a careful examination of the context can determine whether the word is the proper name of the idol (Moloch) or the 3rd personal possessive pronoun for king. The idol is also spelt "Milcom" and "Molech."
Malcam (6 Occurrences)
2 Samuel 12:30 And he took the crown of their king from off his head; and the weight thereof was a talent of gold, and in it were precious stones; and it was set on David's head. And he brought forth the spoil of the city, exceeding much. (See JPS)
1 Chronicles 8:9 He became the father of Hodesh his wife, Jobab, and Zibia, and Mesha, and Malcam, (WEB JPS ASV BBE NAS RSV NIV)
1 Chronicles 20:2 And David took the crown of their king from off his head, and found it to weigh a talent of gold, and there were precious stones in it; and it was set upon David's head: and he brought forth the spoil of the city, exceeding much. (See JPS)
Jeremiah 49:1 Of the children of Ammon. Thus says Yahweh: Has Israel no sons? has he no heir? why then does Malcam possess Gad, and his people well in its cities? (WEB JPS ASV DBY YLT NAS)
Jeremiah 49:3 Wail, Heshbon, for Ai is laid waste; cry, you daughters of Rabbah, dress yourself in sackcloth: lament, and run back and forth among the fences; for Malcam shall go into captivity, his priests and his princes together. (WEB JPS ASV DBY YLT NAS)
Zephaniah 1:5 those who worship the army of the sky on the housetops, those who worship and swear by Yahweh and also swear by Malcam, (WEB JPS ASV)