Hadadezer. Some codices, with four early printed editions, Septuagint, Syriac, and Vulgate, read "Hadadezer" (compare 1 Chronicles 18:3; 1 Chronicles 18:5). Some divide and make it two words.
Zobah. See Psalms 60:1, and compare 1 Samuel 14:47.
recover. Hebrew cause his hand to cover: "hand "put by Figure of speech Metonymy (of Cause), App-6, for possessing.
border. boundary. 1 Chronicles 18:2, "establish his dominion there".
Euphrates. Compare 1 Chronicles 18:3 and Genesis 15:18.