One LORD is a similar expression to One God. This occurs as a name of God in some English versions. Elsewhere it is a descriptive phrase.
One LORD in Hebrew:
Strong’s Concordance numbers: 3068, 259
Bible references: Deut. 6:4 (KJV only); Zech. 14:9 (NIV and KJV only)
And the Lord shall be king over all the earth: in that day shall there be one Lord, and his name one. (Zechariah 14:9 KJV)
NASB has “the LORD is one.” Elsewhere the same Hebrew phrase is also translated “the LORD is one” (Deut. 6:4 NASB, NIV).