What Does “Tetrarch” Mean in the Bible?
Office or title
The ruler of one part of a kingdom. The word means “ruler of a fourth part.”
Today
Like the governor of a region, under the rule of Rome.
Where it appears in the Bible
Luke 3:1; Luke 3:19
What the Bible says
Luke 3:1
Now in the fifteenth year of the reign of Tiberius Caesar, Pontius Pilate being governor of Judea, and Herod being tetrarch of Galilee, and Philip his brother tetrarch of Iturea, and the country of Trachonitis, and Lysanias tetrarch of Abilina;
Luke 3:19
But Herod the tetrarch, when he was reproved by him for Herodias, his brother’s wife, and for all the evils which Herod had done;
Douay-Rheims Bible (Challoner revision), public domain.
Source: NABRE note on Luke 3:1