Lord of Hosts, Lord of Powers, Lord of Armies.
Archimandrite Nikifor’s Biblical Encyclopedia
A Hebrew phrase, frequently found in the Old Testament (Ps. 59 [58]:6 [as given]; Isa. 5:7; Jer. 2:19, and elsewhere), and only twice in the New Testament (Rom. 9:29; James 5:4). The word “Sabaoth,” that is, Lord of Hosts, in the opinion of some, refers to God as the Supreme Commander of the angels; in the opinion of others, it indicates in Him the Supreme Master of the armies of the people of Israel. But more probably this name is given to the Lord in the sense of His omnipotence and His special providence over the world and mankind.