Easton's Bible Dictionary (1897)
Friendly, one who maintained true allegiance to king David (1 Kings 1:8) when Adonijah rebelled.
Smith's Bible Dictionary (1863)
(friendly), a person mentioned (in (1 Kings 1:8) only) as having remained firm to David’s cause when Adonijah rebelled.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
RE'I (friendly), one who remained true to David when Adonijah rebelled. 1 Kgs 1:8.
Hitchcock's Bible Names (1869)
my shepherd; my companion; my friend