sons
Compare (2 Samuel 6:23).
The "five sons" were children of Michal's sister Merab, wife of Adriel, "whom she brought up for Adriel". (1 Samuel 18:19).
Related Commentaries of 2 Samuel 21:8
2 Samuel 21:8
8 But the king took the two sons of Rizpah the daughter of Aiah, whom she bare unto Saul, Armoni and Mephibosheth; and the five sons of Michalc the daughter of Saul, whom she brought up for Adriel the son of Barzillai the Meholathite: