What does St. Gabriel’s name mean?

The archangel's name refers to the "strength of God."

Each of the archangels named in the Bible has the Hebrew word el, “God,” in their name, such as Micha-el (Who is like God?).

This is the same for Gabri-el, which in Hebrew is translated as, “God is my strength” or “Strength of God.” In Latin this is translated as, “Fortitudo Dei.”

The Catholic Encyclopedia expands on the spiritual meaning of this name.

Gabriel is, in accordance with his name, the angel of the Power of God, and it is worth while noting the frequency with which such words as “great,” “might,” “power,” and “strength” occur in the [biblical passages connected to Gabriel]. The Jews indeed seem to have dwelt particularly upon this feature in Gabriel’s character, and he is regarded by them as the angel of judgment, while Michael is called the angel of mercy.

Following this tradition, an ancient Latin prayer entitled “O Fortitudo Dei” is often prayed, seeking the intercession of St. Gabriel.

Here is an English translation of this traditional prayer.

O Strength of God, Saint Gabriel, thou who announcedst to the Virgin Mary the incarnation of the only-begotten Son of God, I praise thee and honor thee, O elect spirit. I humbly beg thee, with Jesus Christ our Savior and with His Blessed Mother, to be my advocate. I also pray that thou wouldst comfort me and strengthen me in all my difficulties, lest at any time I may be overcome by temptation and I might offend God by sinning. Amen.