be borne, (heavy) burden (self), lade, load, put

Concise Bible Dictionary:

Besides the common use of this word, it occurs at the commencement of several prophecies; as “The burden of Babylon,” “the burden of Moab” (Isa. 13:11The burden of Babylon, which Isaiah the son of Amoz did see. (Isaiah 13:1); Isa. 15:11The burden of Moab. Because in the night Ar of Moab is laid waste, and brought to silence; because in the night Kir of Moab is laid waste, and brought to silence; (Isaiah 15:1)). The learned are not agreed as to the force of massa in such places: its natural meaning would be “a judgment that lies heavy on the people;” but some take its meaning to be “an oracle or sentence pronounced against them.” The word occurs also in Jeremiah 23:33-3833And when this people, or the prophet, or a priest, shall ask thee, saying, What is the burden of the Lord? thou shalt then say unto them, What burden? I will even forsake you, saith the Lord. 34And as for the prophet, and the priest, and the people, that shall say, The burden of the Lord, I will even punish that man and his house. 35Thus shall ye say every one to his neighbor, and every one to his brother, What hath the Lord answered? and, What hath the Lord spoken? 36And the burden of the Lord shall ye mention no more: for every man's word shall be his burden; for ye have perverted the words of the living God, of the Lord of hosts our God. 37Thus shalt thou say to the prophet, What hath the Lord answered thee? and, What hath the Lord spoken? 38But since ye say, The burden of the Lord; therefore thus saith the Lord; Because ye say this word, The burden of the Lord, and I have sent unto you, saying, Ye shall not say, The burden of the Lord; (Jeremiah 23:33‑38), where it is “the burden of the Lord.” The false prophets were not to use this expression, as if they had a message from God. If they did, it should bring judgment upon them. The same word is translated “prophecy” in Proverbs 30:11The words of Agur the son of Jakeh, even the prophecy: the man spake unto Ithiel, even unto Ithiel and Ucal, (Proverbs 30:1) and Proverbs 31:11The words of king Lemuel, the prophecy that his mother taught him. (Proverbs 31:1).

Strong’s Dictionary of Hebrew Words:

Number:
6006 (find all occurrences in KJV Bible)
Transliteration:
`amac
Phonic:
aw-mas’
Meaning:
or mamas {aw-mas'}; a primitive root; to load, i.e. impose a burden (or figuratively, infliction)
KJV Usage:
be borne, (heavy) burden (self), lade, load, put