🔼The name Geder in the Bible
The name Geder occurs only once in the Bible. Geder was a royal Canaanite city, which was conquered by Joshua (Joshua 12:13). We don't know anything about this city, but some scholars insist that the city was saved, renamed Gederah and given to Judah (Joshua 15:36). Along with this suggestion comes the conclusion that both David's mighty-man Jozabad the Gederathite (1 Chronicles 12:4) and David's administrative officer Baal-hanan the Gederite (1 Chronicles 27:28) came from Geder or Gederah. There is, however, no proof of this or even any need to assume it.
🔼Etymology of the name Geder
The name Geder comes from the noun גדר (gader), meaning wall:
For a meaning of the name Geder, NOBSE Study Bible Name List reads Wall and Jones' Dictionary of Old Testament Proper Names has A Wall. BDB Theological Dictionary does not translate our name but does list it under the noun גדר (gader), meaning wall.