Gera is a name associated with Benjaminite families, including ancestors of Ehud and Shimei. Several individuals or family lines may be represented by this name.
Historical Bible Dictionaries
Easton's Bible Dictionary
Grain. (1.) The son of Bela and grandson of Benjamin (1 Chr. 8:3, 5, 7). (2.) The father of Ehud the judge (Judg. 3:15). (3.) The father of Shimei, who so grossly abused David (2 Sam. 16:5; 19:16, 18).
Smith's Bible Dictionary
(a grain), one of the “sons,” i.e. descendants, of Benjamin. (Genesis 46:21) Gera, who is named, (Judges 3:15) as the ancestor of Ehud, and in (2 Samuel 16:5) as the ancestor of Shimei who cursed David, is probably also the same person (though some consider them different persons).
International Standard Bible Encyclopedia (ISBE)
<p>ge'-ra (gera', "grain"): A family name of the tribe of Benjamin, hence, not necessarily a separate individual in (3) and (4) below:</p><p>(1) A son of Benjamin (Ge 46:21).</p><p>(2) According to 1Ch 8:3,5,7, son of Bela and grandson of Benjamin. The name is repeated (8:5) in the list of Bela's sons.</p><p>(3) Father, or ancestor, of the judge Ehud (Jud 3:15).</p><p>(4) Father, or ancestor, of Shimei, the Benjamite, who cursed David when he fled from Absalom (2Sa 16:5; 19:16,18; 1Ki 2:8).</p>