Smith's Bible Dictionary 
Ju'nia. (Belonging To Juno). A Christian at Rome, mentioned by St. Paul as one of his kinsfolk and fellow prisoners, of note among the apostles, and in Christ before St. Paul. Romans 16:7. (A.D. 55).
Fausset's Bible Dictionary 
A Christian at Rome, one of Paul's "kinsmen ("fellow countrymen", Romans 9:3) and fellow prisoners who are of note among the apostles, who also were in Christ before him" ( Romans 16:7).
Morrish Bible Dictionary 
A believer and fellow prisoner and kinsman of Paul, of note among the apostles, and who was in Christ before Paul. Romans 16:7 . The name is really Junias
Holman Bible Dictionary 
Easton's Bible Dictionary 
Kitto's Popular Cyclopedia of Biblial Literature