Concise Bible Dictionary:
The AV (KJV) has “the Great [stone of] Abel” (1 Sam. 6:18). Delitzsch believes that this is not a proper name and that Abel is a mistake for eben, “a stone,” the final m being put instead of l: and if so it would be simply “the great stone,” which is also mentioned in verses 14 and 15. This is the rendering adopted by the LXX (Septuagint) and the Targum.