In the list of apostles, Nathanael is called by his patronymic Bartholomaios, as it stands in the Greek, and Tholomaios is referred to Talmai (furrows), which occurs in the list of the sons of Anak, and also as belonging to the King of Geshur, Absalom's grandfather. (Yonge)

Bartholomew]  Bar Talmai or Bar Thalmai, a name of which Schoettgen also gives instances—in Gk. Bartholomaios.  It means "son of Talmai" (the Gk. form Tholomaios is found in Josephus, Ant. xx. i. § 1), and of course was not his circumcision-name but merely indicated his parentage.  From his being put next to Philip in Mark and Luke, as well as here, he is commonly thought to be Nathanael, the friend of Philip, whom the latter brought to Jesus on the day of his own call (John i. 45-7). (E.W.B. Nicholson)