From BiblePortal Wikipedia

Smith's Bible Dictionary [1]

Abish'alom. (Father Of Peace). Father or grandfather of Maachah, who was the wife of Rehoboam and mother of Abijah.  1 Kings 15:2;  1 Kings 15:10. He is called Absalom in  2 Chronicles 11:20-21. This person must be David's son. See Lxx . ;  2 Samuel 14:27.

Morrish Bible Dictionary [2]

Father of Maachah, wife of Rehoboam and mother of Abijam, king of Judah.  1 Kings 15:1,2,10 . But in  2 Chronicles 11:20 we read that Maachah was the daughter of Absalom; therefore Abishalom appears to be a fuller way of writing Absalom, and refers to the son of David. See ABSALOM.

Holman Bible Dictionary [3]

 1 Kings 15:10Absalom

Hastings' Dictionary of the Bible [4]

ABISHALOM . See Absalom.

Fausset's Bible Dictionary [5]

(See Abijah .)

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [6]

a fuller form ( 1 Kings 15:2;  1 Kings 15:10) of the name ABSALOM (See Absalom) (q.v.).

International Standard Bible Encyclopedia [7]

a - bish´a - lom  : Variant of Absalom .