|Easton's Bible Dictionary|
Extension, the son of the giant whom Sibbechai slew (2 Samuel 21:18); called also Sippai (1 Chronicles 20:4).
Int. Standard Bible Encyclopedia
saf (caph; Codex Vaticanus Saph; Codex Alexandrinus Sephe): A Philistine, one of the four champions of the race of Rapha ("giant") who was slain by Sibbecai, one of David's heroes (2 Samuel 21:18 1 Chronicles 20:4). It is supposed by some that he was the son of the giant Goliath, but this is not proved. In 1 Chronicles 20:4, the same person is called "Sippai."
Saph (1 Occurrence)
2 Samuel 21:18 It came to pass after this, that there was again war with the Philistines at Gob: then Sibbecai the Hushathite killed Saph, who was of the sons of the giant. (WEB KJV JPS ASV BBE DBY WBS YLT NAS RSV NIV)