The meaning of the name is explained by the Bible text. Likely it has the implication that the Lord is God in both Canaan (west of the Jordan) and Gilead (east of the Jordan). Thus it does not matter where you live, east or west, the Lord is God and he alone is to be worshipped.1
34 The people of Reuben and the people of Gad called the altar Witness, “For,” they said, “it is a witness between us that the LORD is God.”