Boyd’s Bible Dictionary:
(hairy, or elephant). With Julius Caesar and Augustus Caesar a surname, but with the latter it became official and remained so till the death of Nero. In Luke 2:1, Augustus Caesar is meant; in Luke 3:1, Tiberius Caesar; in Acts 11:28, Claudius Cesar; in Acts 25:8, Philippians 4:22, Nero.
Concise Bible Dictionary:
The common title given to succeeding Roman emperors, adopted from the name of Julius Caesar (Matt. 22:17,21; Mark 12:14,16-17; Luke 2:1; John 19:12,15; Acts 25:8,21; Phil. 4:22). The history of the New Testament fell under the reigns of Augustus, Tiberius, Caligula, Claudius, and Nero.
Strong’s Dictionary of Greek Words:
Meaning:
of Latin origin; Caesar, a title of the Roman emperor
Jackson’s Dictionary of Scripture Proper Names:
severed
Potts’ Bible Proper Names:
Hairy; cutting:― title of the Roman emperor of Judea, John 19:12. {Caesariatus; Caesia}