Lord of heaven is a name of God that only occurs in the Old Testament in Aramaic. There are similar names of God in Hebrew.
Lord of heaven in Aramaic:
Strong’s Concordance numbers: 4756, 8065
Bible reference: Dan. 5:23
When Daniel interpreted the writing on the wall of King Belshazzar’s palace, he said this to the king: “You, [Nebuchadnezzar’s] son, Belshazzar, have not humbled your heart, even though you knew all this, but you have exalted yourself against the Lord of heaven. (Daniel 5:22-23)
Two similar Hebrew names for God are God of heaven and king of heaven. Other names tell of God’s dominion over the earth (God of earth) or over both realms (Lord of heaven and earth and God of heaven and earth).