Mighty Lord is one of several names of God that point to His supreme power. The word khasin can also mean strong.
Mighty Lord in Hebrew:
Khasin Yah
Strong’s Concordance numbers: 2626, 3050
Bible reference: Ps. 89:8
O Lord God of hosts, who is like You, O mighty Lord?
Your faithfulness also surrounds You. (Psalm 89:8)
The KJV calls God the strong Lord in this verse.
Similar names for God are the “Lord Almighty,” “Mighty God,” “Great Mighty and Awesome God,” and “Mighty One.”