Son of Tolmai, one of the twelve apostles (Matt. 10:3; Acts 1:13); generally supposed to have been the same as Nathanael. In the synoptic gospels Philip and Bartholomew are always mentioned together, while Nathanael is never mentioned; in the fourth gospel, on the other hand, Philip and Nathanael are similarly mentioned together, but nothing is said of Bartholomew. He was one of the disciples to whom our Lord appeared at the Sea of Tiberias after his resurrection (John 21:2). He was also a witness of the Ascension (Acts 1:4, 12, 13). He was an "Israelite indeed" (John 1:47).
Easton's Bible Dictionary. M.G. Easton. 1897.