Easton's Bible Dictionary (1897)
The third, a Roman Christian whom Paul employed as his amanuensis in writing his epistle to the Romans (16:22).
Smith's Bible Dictionary (1863)
(third), probably a Roman, was the amanuensis of Paul in writing the Epistle to the Romans.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
TER'TIUS (the third), Paul's amanuensis, to whom he dictated the Epistle to the Romans. Rom 16:22.
Hitchcock's Bible Names (1869)
third