Answer:
The answer is “no one knows”. Here are the two passages of scripture that mention the account:
1 Chronicles 20:4-8 And it came to pass after this, that there arose war at Gezer with the Philistines; at which time Sibbechai the Hushathite slew Sippai, that was of the children of the giant: and they were subdued. And there was war again with the Philistines; and Elhanan the son of Jair slew Lahmi the brother of Goliath the Gittite, whose spear staff was like a weaver’s beam. And yet again there was war at Gath, where was a man of great stature, whose fingers and toes were four and twenty, six on each hand, and six on each foot: and he also was the son of the giant. But when he defied Israel, Jonathan the son of Shimea David’s brother slew him. These were born unto the giant in Gath; and they fell by the hand of David, and by the hand of his servants.
2 Samuel 21:18-22 And it came to pass after this, that there was again a battle with the Philistines at Gob: then Sibbechai the Hushathite slew Saph, which was of the sons of the giant. And there was again a battle in Gob with the Philistines, where Elhanan the son of Jaareoregim, a Bethlehemite, slew the brother of Goliath the Gittite, the staff of whose spear was like a weaver’s beam. And there was yet a battle in Gath, where was a man of great stature, that had on every hand six fingers, and on every foot six toes, four and twenty in number; and he also was born to the giant. And when he defied Israel, Jonathan the son of Shimea the brother of David slew him. These four were born to the giant in Gath, and fell by the hand of David, and by the hand of his servants.
So I would be interested in what the “name is” they give. I would love to see someone prove it to be a specific name and cite their source.
The answer in Hebrew literally means “brother of Goliath”.