Gaius
Easton's Dictionary
(1.) A Macedonian, Paul’s fellow-traveller, and his host at Corinth when he wrote his Epistle to the Romans (16:23). He with his household were baptized by Paul (1 Cor. 1:14). During a heathen outbreak against Paul at Ephesus the mob seized Gaius and Aristarchus because they could not find Paul, and rushed with them into the theatre. Some have identified this Gaius with No. (2).
(2.) A man of Derbe who accompanied Paul into Asia on his last journey to Jerusalem
(3.) A Christain of Asia Minor to whom John addressed his third epistle (3 John 1:1).
Smith's Dictionary
or Cai’us (lord)—
A Macedonian who accompanied Paul in his travels, and whose life was in danger from the mob at Ephesus. (Acts 19:29) (A.D. 54.) Of Derbe. He went with Paul from Corinth in his last journey to Jerusalem. (Acts 20:4) (A.D. 54.) Of Corinth, whom Paul baptized and who was his host in his second journey in that city. (1 Corinthians 1:14; Romans 16:23) (These are supposed by some to be only one person.) John’s third epistle is addressed to Christian of this name. We may possibly identify him with No. 2.